You can blame Darabont for the music, since he included music towards the end of nearly every episode of Season 1, which carried over into several episodes in Season 2 and Season 3.
But honestly, there's some songs I like that I didn't even hear before they were in the show, such as "Civilian" by Wye Oak and "Hold On" by Tom Waits (though I'm familiar with his acting, I never really heard any of his music before). And I was actually pleased to hear the classic "Driver's Seat" by Sniff 'n' the Tears once again (even for only a few seconds) and "Saturday Night Special" by Lynyrd Skynyrd in the show.
Besides, it's not like it's EVERY episode. I mean, I can name more episodes that didn't end with artists music than those that did.
And look at the bright side: It's not some crappy teeny-pop music like Justin Bieber or Katy Perry that they're using.