Having taken some flight courses in high school, and knowing some pilots and aircraft owners, I have been somewhat familiar with the rigorous maintenance that is required for airplanes. Thus, when I flew on the 909, I assumed that it was maintained in tip-top shape.
The crash investigation report says that the foundations point of contact at the FAA died, and was not replaced. The foundations emails regarding their regulatory compliance went unanswered, so eventually they quit sending them and continued operations with no FAA oversight.

I would think that someone at the Collings foundation would know this would catch up with them. Perhaps the deceased pilot/head of maintenance was the only one who knew? I think it would be easy for an organization like this to rely too much on the judgement and performance of one or 2 highly experienced volunteers. But if they get lax, where is the oversight? Obviously not the FAA.
This highlights the folly of relying on government bureaucracies to watch over our safety. Why can't someone at the IRS croak so I can quit paying taxes?