FWIW & IMHO:
Just because a car is driven, that does not mean that it is not still in existance. Stolen: well, those might still be intact, but we'll never see them because they are probably not in the U.S. And crashed: well, I am sure that some of those crashed were restored. Oh, you wouldn't want one of those. Well, me neither, but it could be a good possibility that a "Salvage Title" GNX that has been restored could still be worth owning. I also have known of a few people that have considered the GNX as an everyday vehicle, but I know of a lot more that kept the mileage and use as low as possible because they thought that they were/are something special and would ond day be worth something.
I would still believe that there are about 500 left out there intact.
Definitely not all museum quality vehicles, but still owned, running, and intact.