I'll admit I haven't read this whole thread, but here are my 2 thoughts on provenance:
1) The notion that provenance should be required legally or by norms in the collecting community, or that coins without provenance are substantially less desirable, is worrisome to me. There's no doubt that this trend is on the rise, and it has been the case for years now that in certain situations (transporting coins internationally, etc.) it is indeed legally required.
I understand all the reasons why, but the fact that this trend has bled onto coins that are legally "jailbroken" from MOUs, etc. is a problem. It is not reasonable or beneficial, in my view, to pursue a system where every coin in every collection globally has traceable provenance or is otherwise tainted.
2) All that said, provenance can be extremely interesting and therefore valuable. I don't understand the comments here from people saying they don't care. Maybe they have in mind the above issue. But I don't see how you can be interested in history (which is really the genesis for any interest in numismatics) and NOT be fascinated to know specific ownership history of your coins, especially if they were owned by prominent collectors or historical figures.
In other words, if you think a piece of ancient Greek or Roman history is cool, how do you not find a piece of Greek/Roman history owned by former US President John Quincy Adams 2x as cool?? (Just a random example)