It's creatively exhausted. Pop music today has the same problem "classical" music faced at the end of the 19th century: there's a very finite number of chords and chord progressions that sound "right" to the human ear, and we've used them up.
If that's OTT, think about pop music post-Elvis and pre-Beatles; there was a ton of Brill Building dreck out there.
If that's OTT, think about pop music post-Elvis and pre-Beatles; there was a ton of Brill Building dreck out there.