> On the other hand, every single generation can give detailed accounts of how much more real and alive and authentic the world was a few decades ago.

I don’t know that this is true, and I doubt it meant the same thing to Plato as it did to us; I read somewhere that in ancient times, nostalgia would have been for the world of the gods, not a specific time and place.

The thirties and fourties’ were probably not more alive and authentic than the 50’s and 60’s. The 1920’s were a cultural peak that retreated until the 1960’s, and prior to the Industrial Revolution, things didn’t change fast enough for like decades to be significant. The original documented example of nostalgia was about soldiers nostalgic for home, not explicitly their youth or another time.

All these feelings, “nostalgia” are going to hit different without shared cultural experiences, and changing technological and aesthetic context,