> I feel like there's more music than ever, but none of it seems to be of much value and/or lasting cultural impact.
It's always been that way, especially before mass-produced recordings were available.
The "Beatles" period was partly because you had to choose wisely what you were going to spend your limited dollars on when you went to the record shop.
The difference today is that recording technology is cheap, and, with streaming, you don't have to "choose wisely" when you go to the record store. Now all of the mediocre artists, who were generally excluded from the "Beatles" period, can get on streaming platforms.
BTW: There's awesome music coming out today. It just takes time for word to spread.