That might be true if the Greek people had been in a position to care about the marbles at the time.
I must do more research, since this is the era where re-writing history is not only common, but seen as an "obligation" by the more "progressive" members of academia.
As I remember it, the Elgin Marbles were in the process of being ground and sold for mortar at the time they were purchased. All of the remaining building where they came from was, in fact ground for mortar. Had the Elgin Marbles not been purchased, there is zero chance that they would now exist. How that translates to stolen property... and ..rightful owners... can only be the product of a deranged, selective "progressive" mind.
I don't think so. Unless I'm completely misinformed, these marbles decorated the exterior top of the Parthenon, which is definitely still standing.