So I have been thinking this for a long while now, basically the album SMiLE by the Beach Boys was produced (somewhat) but was scrapped on May 6th 1967, just before The Beatles released Sgt. Pepper's Lonely Hearts Club Band.
I was able to listent to a lot of the original recordings (I played Carl Wilson in some movie), and the music while different was exactly what Brian Wilson termed it "A teenage symphony to God".
Would SMiLE have changed the way music evolved? (5 songs to listen to)