Oasis were around from 1990/1 anyway - they formed before Blur got really big so they would have been around anyway. I doubt that if Blur hadn't been big Oasis wouldn't have succeeded - it would have happened no matter what. They had the tunes that people liked - plus, Oasis were different from Blur in musical style and attitude that there isn't much cross-over. Oasis actually succeeded from where the Happy Mondays and Stone Roses left off - why those two weren't included the 'Hall of Fame' is a more pertinent question...