There were attempts, but audio CDs were specced in 1980, and nobody was ever able to sell breaking compatibility with the existing (substantial) CD player ecosy

There were attempts, but audio CDs were specced in 1980, and nobody was ever able to sell breaking compatibility with the existing (substantial) CD player ecosystem. There's a summary of the context here: https://en.wikipedia.org/wiki/Compact_Disc_and_DVD_copy_protection#Changes_that_followed https://en.wikipedia.org/wiki/Compact_Disc_and_DVD_copy_prot...