I found that quite depressing - all that history, effectively stored outdoors & neglected for so long that the rust has just about won ! To restore, most cars would probably cost up to $1m, & then it would not really be a restoration - the original cars would only be capable of providing patterns from which new panels & parts would have to be made. So then you end up with replicas !
Perhaps most of them are best preserved as-is : a stark reminder to future generations that heritage should be respected !