Many times what happens is that the "within" innovation is not so much innovation in itself, but the innovation is including aspects that were done by the avant

Many times what happens is that the "within" innovation is not so much innovation in itself, but the innovation is including aspects that were done by the avant-garde decades before, into a popular context. avant-garde composers were playing with recording and editing techniques for a long time before the beatles came and used those ideas in a more catchy way, with a hairstyle to boot. The innovation is closer to the business side than to the music itself.