In France, it is very common to use existing Roman ruins as theaters, or locations for music and music festivals.
For example, the world famous Nice Festival du Jazz that attracts the finest jazz performers is held yearly at Cimiez, the ruins of a vast Roman complex on a hilltop in Nice.
The Arena at Arles, is used for bull fights to this day. The setting for Opera in a grand antique space is extraordinary.
The French don’t consider this a Museum, but something very much alive and useful in the present.
Yes I know - I remember being at the Coliseum in Arles. I was just commenting about how the author said that they were “transported back 2000 years” while watching Carmen, which was written in the 1870’s.