There's constant restoration work happening in the Parthenon but it's slow moving because restoring something ancient while preserving it and not destroying anything else is hard, meticulous work.

At the moment they're literally piecing together rock fragments to reconstruct the original pieces and where that is impossible they're building new ones from marble which is very similar to the one used in the original construction.

Here's an article from 2019 with some pictures.

Edit: Also, keep in mind that while the Greek identity has existed for thousands of years it has morphed and shifted and evolved. Athens itself has been conquered and administered by a number of empires, and does not have a continuous history as a major city or capital. Cities rise and fall and in the early 1800s Athens had a population of five thousand (yes, thousand) people. It was a forgotten backwater.