It'd be a bad thing. All You Need Is Love wouldn't work as a large-scale philosophy, it'd be an excuse for, like, crazy anarchy and it would probably only be corrupted and turn violent (could you argue that AYNIL is a vaguely Communist sentiment? Imagine definitely is.).
Plus, people would have to be made to listen to the Beatles- and no one likes something they're made to do, right? So no one would like the Beatles anymore, and what kind of world would that be?!