I'm not sure that's true, at least for music we've seen an explosion of covers and style remixes. Depending on the popularity and virality of a song, you can often find between dozens to hundreds of different covers of varying quality. And there are artists dedicated to converting popular songs into various other genres.
Used to be, almost everyone learned to play an instrument. Families would play together around the fire, or children who excelled would be invited to perform to entertain at their parents' party.
Sheet music was the "Top 40" of the pre-Edison days, and people made good livings writing it.
OTOH, mixes and remixes, greatly spurred by innovations in rap, have proliferated in the last 30 years. But that's not the same pervasive skill set in society.
