Today, it's mostly true that everything is available. The music that reaches the masses, though, is defined by production over musical quality.
Would we even see or hear from Cass Elliot, Janis Joplin, or Patsy Cline today? Producers would choose someone other than Patsy Cline for Crazy and twist Willie Nelson's arm to make him a ghostwriter on the song so the hot, autotuned, woman could claim she wrote it herself.
There is more to it than just getting older.