As we all know, the fall of Rome (ca 475 AD) brought a period of chaos to Europe-called the “Dark Ages”. Later, (ca 1000 AD) Europe became a patchwork of indpenedent monarchies, with society organized under the so-called “feudal” system . This was when a local ruler owned an estate (demesne0, and all of the peasants (who farmed the land) worked for him. The aristocrat class were the elite warriors (knights), and society was rigidly structured. This went on for hundreds of years-but ended with the rise of powerful national governments (kings). So what ended the fun? Was it the rise of trade 9and the merchant class emerging)? Or the Black Plague-did it upset the civil order? Or the simple rise of population of the serfs-who realized that they could challenge the power of the nobility?Could a technological-based civilization emerged under feudalism? or were the requisite underpinnings (education, economic need, etc.) just not present under feudalism? Will Durant (not a serious historian) put the end of the era to the rise of trade between states, and the rise of the merchant class. Other historians have cited the Crusades, Black Death, etc., as causes. What do modern historians feel? incidentally, we mark the passing of Dr. Eugen Weber-a great historian and an inspiring teacher! 
A lot of it had to do with the results of the Plague. The following labor shortage caused the value of the serf’s labor to increase by leaps and bounds. The higher wages led to increased political unrest as the remaining landholders tried to reassert authority. Toss into the mix the rising nation-states and their rulers and feudalism as an institution was doomed. You pretty much hit it in the OP.
I agree. The OP listed a lot of factors and the answer is YES to all of them.
Nationalism killed feudalism, IMO.
Which is sort of funny as Kings helped promote nationalism to unify their kingdoms.
Feudalism didn’t really help the kings directly. The people who really benefitted from feudalism were the lesser nobility, who gained the obedience of the peasants. Kings had relatively few peasants directly in their service - most of their vassals were nobles, who historically took a looser view on the obedience they owed their sovereign.
So when feudalism grew weak (due to the factors mentioned in the OP) the kings turned on the nobility and essentially told them “how’s it feel when your vassals question everything you tell them?” and used the opportunity to reduce the powers of the nobility. And then the kings promoted nationalism because as the personification of the nation, they benefitted from nationalism.
A good negative example of the problems of feudalism is the War of the Roses. Too much power in the hands of men with equally dubious claims to the throne is a bad thing. According to Frances Gies, one reason that knights began to have more status in the mid to later middle ages was that Kings were giving them much of the judicial powers/duties previously held by nobles. This diluted the nobles power while creating more loyalty among the lesser fighting class. It also provided a limited form of meritocracy and social upward mobility.
Kings like Henry II took even more active steps to squash problematic barons. He fought them militarily and physically destroyed their castles and forts. Of course, Henry II didn’t have to deal with such powerful vassals as existed during the late 1300s.
In his series “Connections,” James Burke leans to the Black Plague being the most influentual cause of change from the feudal system. Not only did it upset the civil order, but as silenus pointed out the labor shortage caused a rise in wages.
Burke also liked to say that when one-third of the population quickly disappears, the remainer inherits what that one-third had. So you’re looking at a change in the social order.
I have read that feudalism ended (in England) when Henry VIII outlawed private armies-henceforth, there would be only one english national armie, raised and commanded by the king. So a strong monarch seems to have been a prerequisite, for the end of the old feudal system. Were people of this period (16th centry0 nostalgic for the old era? Feudalism was probably pretty lousy, for everybody except the people on top-but did anyone else lament the passing of this period?
I hate to focus too much on one factor because that belies the very complex interactions that create new societies. But to describe one way that the plague destroyed old social orders is that the old orders could not adapt to the changes. Cities and rural populations were both being laid waste by the plague. But in the city, work was (usually) done by free men who had geographic mobility and much greater options than a peasant. Even more importantly, the employers in the city were merchants who bought their labor with cash. Out in the boonies, the lords got their labor through peasants who owed it to their lord by consequence of birth. So when the plague took a third of the labor force, the merchant could hire new men (at a higher price). The often cash-strapped lord (his wealth was in the form of real estate and therefore less liquid) had a much tougher time getting new workers. Itinerant harvest workers could demand more payment than simply the bread and ale they formerly got. And if the lord wanted to attract permanent farmers, he had to offer a better deal than his neighbor.
I guess one way to say it is that the plague reduced the importance of social class relative to economic power. And with wealth increasing throughout Europe, this meant that peasants now had more real power.
Shadows of Feudalism exist, in the hierarchical structure of the military, & in civilian bureacracies.
In the case of the military at least, I’d say the shadow is faint indeed. The idea of military hierarchy long predates the feudal period under discussion here. And it lacks some important elements: an economic motive on the part of the lords, and the structural fluidity under which a lord could contemplate the conquest of additional territory.
Feudalism != Hierarchy.
Military hierarchies, including dedicated officers corps, long predate European feudalism and so, too, do bureaucracies.
Take the example of the Roman military. Rome wasn’t feudal until the barbarians took over, yet the officers were invariably drawn from the aristocracy. Note that having a class of aristocrats is not the same thing as the feudal system.
It’s also important to remember that it’s sort of an open question as to whether a “feudal system” really existed in the first place.
To answer this portion of the question, I’d say that it would be possible but extremely unlikely to emerge in Europe. Feudalism was extraordinarily fractured, so Europe was thousands of individual, separated communities. There weren’t the same major nation-states as we think of Europe today - France was not a nation in any modern sense, it was a collection of nobles who agreed to follow the French king, but they didn’t really cooperate in terms of education, healthcare, or military except in extraordinary circumstances.
This isolation and fragmentation makes professional specialization of occupations very difficult. For instance, a cannon-maker wouldn’t have much demand in a feudal world. One can’t imagine a feudal lord needing more than several cannons, and yet making cannons is a complex trade that would have required dedicated professionalism. With such low demand, there’s no chance for cannons to emerge technologically, really. Once the nation is unified, however, and the cannon-maker starts producing them for the national army of the king, there’s much more incentive for that technological development.
The plague also damaged much of the power and credibility of the Church. Priests died in massive numbers because they presided over funerals and thus were close to infected carcasses. This led many to question whether God was on the Church’s side because apparently he was killing all the priests. The decrease in the Church’s power left a vacuum for secular leaders to take stronger control of government and society.
Why did I think it was gunpowder that ended feudalism?
Gunpowder ended the reign of the mounted knight as arbiter of battles. The Welsh longbow gave it a push in that direction; gunpowder put an end to it. Once you could get a musket to fire with anything like rapidity (1+ round per minute), and after Maurice of Nassau formalized the steps in reloading into an easily learned set of therbligs, and after Gustavus Adolphus took the giant step of relying on muskets without the accompanying pikes to protect from charging cavalry, the day of the knight was over.
It was several pulls…
In the middle ages, you had your peasants (in Spain serfdom the almost-slave way I see it described was pretty much nonexistant, although the term siervos de la gleba exists), which were a lot and had little power and little responsibility; your nobility, who had to be able to feed, clothe and equip a chunk of army - usually, their main source of income was land; your cityfolk, who in some locations held less power than the nobility, in others as much, in the merchant cities more but only the oligarchy (Barcelona, Venice); your king, whose power was heavily restricted by the nobility, the oligarchy and the Church.
Some pulls:
- there were parts of Europe where the King decided to take over the Church (England); this reinforced the power of the King in front of the nobility and of the Church
- parts where the “bases” decided to take over the Church (the protestant areas); depending on the flavor and on the reaction of the rulers, this could strengthen or weaken their position. In any case, it led to a restructuring.
- Kings started sucking more and more power into their own hands, often disregarding the laws of the land altogether. Through much of the Middle Ages and even in lands without derecho consuetudinario, and partly due to the lack of literacy, orally-transmitted and consensually-born tradition often had as much weight as written law or more; these unwritten traditions fell overboard whenever kings could give them a good push.
- The importance of “living at court” grew, for nobility. If you wanted to have influence with the King, you couldn’t live on your land and wait for the traditional yearly call to Parliament, now you had to go see the King… and preferably stay where he could see you.
- The printing press and relatively cheap paper meant easy access to books. The importance of this can’t be overstated. How many medieval plays and poems have survived? Almost none. What, didn’t people in the Middle Ages invent plays and write poems? Oh, they did… they just did not write them down. Many things which previously weren’t put in writing because the cost was greater than the value of those things, now were written down.
- Gunpowder.
- During the M.A., the majority of an army would have been formed by serfs and freemen, who were equipped by their captain, who in turn got money from the land on which those serfs and freemen worked. The Renaissance saw a lot more mercenary armies and a lot more armies that were equipped and paid (or not…) directly by the Crown. This doesn’t mean that mercenary armies didn’t exist during the M.A. (Swiss mercenaries and the Almogàvers come to mind), but the ratios changed.
I always find it kind of funny that the idea most people have of a feudal king’s level of authority has nothing to do with feudal kings - it’s from Renaissance kings (Louis XIV is the one they most often think of, even those who don’t know the name quote his “I am the State”) who had sucked up as much power as they possibly could.