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When considering purchasing an instrument based on its impressive provenance, realize that the or those former owner or owners sold it, rather than choosing to keep it.
If it's good it's good, if it's not good it's not good.
A very large percentage of amazingly great players have purchased some very bad instruments, but I would strongly suspect that most of them sold those instruments either shortly thereafter or after those particular instruments collected a certain amount of dust.
If it's good, buy it, create your own provenance with that instrument, and - assuming you're never able to find anything better - keep it until you can no longer play.
me...??
I've sold some remarkably fine (personal use) instruments, but I'm sort of a weirdo, in that I try to govern myself into only being a player, while trying to avoid being a collector. (I've also bought a few bad ones, during my several decades long learning process, which hasn't ended.)
my own stubborn lack of willingness to "agree to disagree":
An instrument that may be bad for someone maybe great for someone else.
I seriously doubt that, and suspect that people who hold on to bad instruments are simply oblivious.

