That's the exact reason that most pop music is marketed at teenagers. For them, it's the first time they've heard it (relatively speaking). As you get older, you've heard all the 4/4 C-major stuff you can stand. Even if you're not particularly musical, you will still subconciously recognise that pop songs are repetitive and fairly unoriginal after a while. But it's an easy sale for the record labels, so that why they do it.

That doesn't mean that there doesn't occasionally come along a good song or two. It's still perfectly possible to write a 4/4 song in C and have it be interesting/fun/good to listen to. Unfortunately you'll have to wade through a whole load of crap in the pop charts before you find it ;)