What does "idea qualitatively about the nature of those [entities]" even mean?
There is a difference between knowing what and who. Knowing what can be done pseudonymously. Knowing who requires guns. Which is it, what or who?
One example would be as I mentioned earlier: How much mining gear is sitting in someone's home-office relative to how much in liquid cooled racks in a datacenter.
I'd also really like to know about jurisdictional distribution of both mining and transfer nodes. I think there are some maps, but such things are fairly easy to fake (and usually fairly dubious even when they are not faked.)
A more ideal system would make some of this stuff more known with higher reliability for operational reasons while preserving as much anonymity as possible. But as I've said before, Bitcoin is what we've got and it's not likely or even possible that it will change in such ways.
I agree with you, but that is the future, not today's reality. Mining will one day be done almost entirely by datacenters. You may not know exactly where they are, but they will be well protected by very large guns. Bitcoin doesn't need jurisdictions because you know you can't trust anyone, you can only trust the protocol and how it is engineered to balance mathematical security and networking limitations. If a major mining firm is going to overtly attack the network, it will destroy their investment. If they attack an individual, then it is best that you remain as anonymous as possible.
you are anonymous? That doesn't actually seem like it should be a hugely challenging technical problem if there was sufficient pressure to do it (such as the forfeiture ones mining gear for example.)
If "forget about anonymity" then can you tell me what it is about Bitcoin that makes it particularly worth supporting or using.
My answer would be 'counter-party risk protection' but to say the truth there would be so little else that I would pretty much be forced to move on to more promising pastures (which also provided counter-party risk protection as a minimum.)