What surprises me is that there wasn't a foresighted bureaucrat who said "weve paid for all these, lets make a museum of the significant ones" same on the UK side. What happened to the first Mustangs fitted with Merlin engines for example.the paper work may have been enourmous in the US. When a prototype was built on contract with US government funds it was invariably government property. After delivery and testing, it was government property. It probably remained a hangar queen until a bureaucrat officer said get it out of here and scrapped.