Indie music as a genre doesn't exist.  The music a band makes cannot be categorized based on whether or not they're signed with a label or not. 
So, basically, the problem with pop, or metal, or jazz (etc) occurs when people stop treating the art simply as an art and more like a way of life.  People don't listen to The Backstreet Boys because it's 'gay', avoid 'My Chemical Romance' because it's 'emo' and Chrisitina Aguilera because she's a slut and this, before they even take the time to listen to their songs.   
This, I think, is the problem with modern music, be it pop or anything else.  It is marketed as a way of life instead of a way of communicating emotions.  However, this doesn't mean current artists aren't as good as older ones, its just how they are presented. 
And saying that all artists in a given genre sound more or less the same... well it's a given since the concept of genre wouldn't exist if there weren't similarities between the different songs.  And I don't think all pop artists sound the same more than metal,  rock or jazz artists do.