It’s been over 5 years since the LIGO’s first few detections of gravitational waves from colliding black holes, neutron stars, etc. Looking at the Wikipedia page, there are now dozens of verified events detected by LIGO. Has all of this data led to any new, or at least refined, understanding of the universe? Also, it seems everything detected so far has been from areas of the universe very far from us, which of course means that they occurred a very long time ago. Why aren’t any closer more recent detections being observed? Is it due to the universe being more volatile in its earlier days? I understand that if any major collisions happened too close to us, we probably aren’t here any more to observe them. Also, the area of space that can observe increases exponentially the further out we go, so is it just due to anything close being way too small of a space to expect any major events?
Because much, much more of the universe is far away from us than is close to us. It is the same reason you hear more often of plane crashes in some other country than you do of ones in your yard. (As you mentioned later, I see.)
I’m basing this only on a brief look at the list of observations so far, but it looks to me like there’s a very wide range in distances and the logical conclusion is that you are correct that these are rare events and that it’s just that the probability is much larger of one happening in the very large volume of “very far from us” compared to the mindbogglingly large, but still many orders of magnitude smaller volume of “not very far from us”.
More specifically the volume of space increases as the cube of the distance. For every doubling of distance you include eight times as much space. That provides a very healthy bias for stuff further away.
OTOH, signal strength drops with the square of distance. So that biases against detecting events with distance, but not as heavily as volume increases them.
Overall there are not enough events with good enough error ranges to do much more than say that the numbers of events and distances looks reasonably sensible and isn’t wildly inconsistent with an even distribution system in space.
With significant distance we get to the earlier of universe. But we can’t detect events far enough away that that matters, at least for the moment.
New types of black holes, and a possible partial answer to what dark matter is. This is off the top of my head - the first LIGO detection of gravitation radiation was from the merger of two black holes, each of mass between 10 and 100 solar masses. Black holes in that mass range were expected to be rare, since there wasn’t a good theoretical mechanism for making them, and they had not been observed previously. LIGO and other GW detectors have since found several black holes in the 10-100 solar mass range. If there a are a lot of BHs in that category, it might explain some of the effects from dark matter. BHs make a good candidate for dark matter - they have mass but don’t emit light (except for the accretion disk, so they may not be the only component of dark matter.)
Also, measuring something to an accuracy of a few parts in a billion trillion isn’t good enough for you? 
Eh, not really. The biggest problem concerning dark matter is that whatever it is has to be non-baryonic in origin: Based on the relative abundances of various isotopes of hydrogen, lithium, and (I think) beryllium, we can make very good estimates of how much baryonic matter (that is, matter that’s mostly protons and neutrons by mass) there ever could have been in the Universe, and that amount is far too low to account for the current mass density. Sure, there’s some baryonic dark matter, but most of it isn’t baryonic, and so we don’t know what it is. Strictly speaking, black holes are non-baryonic (a black hole formed from any sort of matter would be indistinguishable from any other), but holes formed from collapsing stars would have been originally baryonic matter, which is what counts for this.
Now, there could be black holes formed from non-baryonic matter, but that doesn’t bring us any closer to the question of what the non-baryonic matter was to begin with.
Thanks for providing more accurate info! I remembered that black holes could only be part of the solution, but had forgotten why. The composition of dark matter is such a thorny question.
Does a primordial black hole need to be made of baryonic matter? If not I would guess that could provide an escape clause for having lots more.
If we detect an over abundance of mid sized black holes merging, how many do we need before it starts to affect calculations of the matter balance of the universe?
If there are lots, we will have to account for the mass somehow, baryonic or not.
I guess such questions are what LIGO will potentially answer and maybe point to major changes to cosmology.
A kugelblitz being an example with a fun name:
The total volume of space increases with the cube of the distance. But the volume of space at a given distance only increases with the square of the distance. It is surface area times depth (roughly) and surface area increase with the square of the distance. So the number of likely sources falls off at exactly the same rate as the signal strength.
Is it a good thing that all of these detections have been far off? If one occurred on the other side of the galaxy, would that be a Very Bad Thing?
Nah. You’d have to be right on top of it, like in the same stellar system, to even notice these gravitational waves macroscopically. There may be other effects that are dangerous. Such as the radiation from a neutron star-neutron star merger, which we’ve also detected with LIGO. That is, LIGO detected the gravitational waves from the merger. The radiation of the NS-NS merger was detected by ordinary telescopes.
Leading to Olber’s paradox.
Primordial black holes would be non-baryonic, and so they are, in fact, one possibility for the missing dark matter. But there’s a heck of a lot we don’t know about primordial black holes, including whether any even exist at all. There are methods to look for them, but there’s still a lot of very large gaps in between the constraints we’ve set using those limits.
And yeah, when you see the energies involved in events like black hole mergers, it’s quite surprising to find that they have so little effect. Gravity is just really, really, really weak.