re: Kanye fans have no idea who Paul McCartney is

25 might be a little old for the cut off. I'd say that probably a pretty big proportion still know. It's old enough for a good amount of people that age to have parents who grew up listening to the beatles.

The 20 a younger crowd are probably starting to get pretty distant generationally from the beatles. Young teenagers probably don't have much of a clue.

Otherwise there will always be a large group who aren't aware of history or where they came from at all.