It depends on the definition of lost. I would argue that an artefact is better protected in a museum in Washington DC rather than in a country in a state of civil war.

Then the debate isn't so much about being lost, but whether the artefact should be located in the country where it was originally created, thousands of years ago.

And I think you can see it both ways. I don't understand people who identify themselves to the population that lived on the same territory centuries ago. It is a different people, a different culture, and there might be some trace of that culture left (like there are traces of the roman empire culture left all over europe), there might be some artefacts, some monuments left. But they are really a foreign people to the current inabitants. So should St Mark's Basilica in venice be destroyed to return the looted parts to Turkey? Or should the Lyxor obelisk on the place de la Concorde in Paris be returned to Egypt? I don't think so.