Hola Daniel,
I will have to disagree with you. Flyign day in and day out from Chino, those rare planes have more than their share of attention. As far as the parts getting rare, it's fairly irrelevant as they are ususally brand new, just fresh out of some metal shop.
As far as the structure is concerned, those planes are not that "complicated". I mean by this, there is no rocket science in the restauration process and on how to put everythign together rigth. Plus, metal sheets, ribs and rivets, a standard on "solidity".
Hey I'm way more concerned about doing aerobatics in my 1967 Cessna 150 inspected by a sunday mechanic than riding in any of Chino's museum bucket.
How often do you see a wing ripping of one of those WBs at airshows? It's usually pilot error, or engine failure (which alos happen "a lot" in General Aviation, but GA planes gliding way better, it's usually a less dramatic consequence).