Because the Greeks had, and have no appreciation of anything from which they cannon derive immediate profit. Sure, let’s just stick them back on a dirty, disheveled tourist trap of a once great site and let the wonderful Athens air degrade them.
To say nothing of the stray dogs and cats using them as a toilet.
When the Greek economic crisis hit, I was wondering if Greece was going to push the Brits for a bailout as an exchange for the Elgin Marbles. I am only half-joking here.