Just an argument to play devils advocate; I once had a conversation about comic book values with my Dad. He told me that if I can't walk into a comic book store and sell an issue "valued" by the price guide at $100 for $100, it isn't worth $100. Sure, we could unionize and standardize the price at $20k, but until they were selling at that price consistently (as opposed to just one poor schmuck who overpaid), then the value wouldn't be at that level.
And to play devils advocate to that, yes we could unionize and standardize our ASKING prices at $20k, but we'd also have to show the solidarity and consistency that included being willing to PAY $20k when we (as current or past owners) were looking to BUY one.