If popular music continues to follow the trend it's following right now, lyrics will consist of 4 different lines repeated over the course of 3 minutes by someone with decent looks and an extremely mediocre voice enhanced by technology. The music backing the lyrics will be either 1) so barebones, it's a bass beat and a weird synth line or 2) a jumbled mess.

Obviously, all kinds of music will continue to be produced. People still produce orchestral music. There is new bluegrass coming out. There's new jazz coming out. They haven't died off.

Music will continue the trand of getting shorter and shorter as we find ourselves multitasking more and more.