As an aside, the idea that financial markets were stodgy and dull before young d-bags ordering bottle service in expensive clubs ruined them seems a bit odd. As long as there have been financial markets, there have been financial market crashes (e.g. Tulipmania in the 1600s, the South Seas Bubble in the 1700s, railway stock speculation in the 1800s, etc.).
Maybe the best description of the OP’s phenomenon is simply “boom and bust”.
I would say that the core problem for the OP’s question can be summarised as “the lure of easy money”. As hogarth notes, there have been booms and busts pretty much ever since we have had money in its modern form. Once you have a rising market, any fool can make money. At least for a short while. Add to that an ability to use other people’s money, and you have all that is needed for arbitrarily bad behaviour.
JK Galbraith notes that “leverage” - basically the ability to invest more money than you actually have - is a very old invention that is re-invented with new clothes every few decades and always leads to the same outcome.
I think that reinforces my point: thinking that an MBA from Wharton is the best indicator of talent is the sort of think a good-but-not-amazing person might think. But if I am a genius innovator, I don’t give a shit where you went, I care what you know, what you can do, and how hard you are willing to work–and I know how to identify those things. In the early stages, there’s a good chance I know you through a network or by reputation, which can be a much more effective way to hire than a cattle-calll. Every decent boss I ever worked for remembered everyone they had ever met, and when we had a vacancy, they had some people they’d been keeping their eye on. That’s less and less practical as an industry grows.
Pointy-Haired Boss: “I like to hire people who are smarter than me…”
Dilbert: “So basically what you’re saying is, you’re the dumbest person in the company?”
I’ve see the situation where the company is on a downward spiral, due to market conditions. The negative climate encourages people to leave - those that have options. So the leftovers are those who for some reason can’t go. Some have only a few years until pension (remember pensions?), some are not that competent, etc.
I think the best expression to cover the OP’s question is the “bandwagon”. When someone has a good idea and succeeds, everyone else wants to pile onto the bandwagon and do the same. Some are successful, some not. After all, for spreadsheets we use Excel today, not Visicalc or Lotus-123. Each had a good run; Visicalc was the original, the others were imitators who jumped on the bandwagon but improved upon it. We remember the notable successes.
The other description is the “river of money” principle. When there’s a river of money going by, everyone runs over to dip their bucket in. (Wall Street is probably the biggest and longest running example of this.) Some are legit and not too greedy, some others are not legit or are too greedy.
But the point of the OP is that for most of those markets there was a point where it wasn’t just a scam. Originally I am sure the 17th century tulip market in the Netherlands was dominated by people who understood the technical details of different types tulips and how to grow and transport them. But then the market exploded and hucksters who knew nothing about tulips got involved.
I wouldn’t be surprised if you saw what you are seeing now with VR and blockchain (or AR). You see the same spammy PR materials that a year or two ago were trying to sell a VR-related scam are now selling a blockchain-related scam (though presumably in the 17th century it was harder to search and replace “sugar” with "tulips 
)
So is there a distinction between natural market cycles and speculative bubbles? In my mind, there is. Like an industry like steel or natural gas might ebb and flow, depending on a variety of factors like the weather, population, technological advancements, whatever. A bubble, to me, strikes me as something that fundamentally lacks legitimacy and most people recognize it, but yet because people seem to be getting rich off the bubble, others invest thinking that they can get out before it bursts.
As it relates to my OP, I think the initial success of legitimate industries (say, mortgage backed securities or internet stocks), potentially attracts potential conmen, scammers and get-rich-quick artists that can ultimately lead to a bubble.
Like why did tech stocks become a bubble in the late 90s? Sure, the internet was new and wonderful. But it’s not like the tech industry didn’t already exist for decades by then. Something about the dot com era lent itself to any idiot thinking they could make money off of the internet and plenty of people willing to give any idiot enough money to try.
For what it’s worth, there are those that argue that tulip mania wasn’t as bad as is usually claimed: