Well great songwriters (especially rock stars) probably have egos that get in the way of collaboration with their equals, i.e. being in a band together. The flu

Well great songwriters (especially rock stars) probably have egos that get in the way of collaboration with their equals, i.e. being in a band together. The fluke of the Beatles was that they both started collaborating as school boys, and both turned out to be top tier songwriters. This also let them develop a healthy working relationship (when The Beatles split up I don't think their talent diminished, at least not for another 5 or 6 years, but there was much weaker quality control and not as much variety in there albums). With respect to the other bands mentioned, I don't think they can claim to have multiple top-tier songwriters. Maybe in the 3-5 classic songs range but not in the 10-30+ range.