Most of what happened before 2000 doesn't seem to exist in cultural memory.

It's not quite true that nothing that happened before 1950 exists at all. But you're not going to find many people who are interested in the art, music, literature, design, or architecture of earlier decades - never mind centuries.

It's as a big a break as there was in the 60s. For that generation the 50s were still an influence, but anything earlier pretty much just disappeared.