Was there a time when popular music wasn't mostly bad? Before the discovery of auto-tune, they must have done lots of manual-tune involving lots and lots of studio takes and other magic.
The 1990s had moments of unexpectedly good, non-traditional music that brushed the mainstream, with stuff like the more "eclectic" grunge bands (Soundgarden, STP, Alice in Chains), metal (Tool), Industrial Rock and Industrial Metal (NIN.)
>Was there a time when popular music wasn't mostly bad?
The 1960s? The Beatles for example were extremely popular.