I made it a point to expose my niece and nephew to good music from the time they were babies (I have no kids of my own).
They're HUGE fans of They Might Be Giants - bigger than me, even. Sing their songs constantly - know them all by heart.
Now they're teenagers.
Now my niece likes One Direction.
After supplying her with a lifetime of good music, and giving her all the tools she needs to identify and appreciate good music, she suddenly decided she likes One Direction because her friend likes One Direction.
I practically exploded like a volcano when she told me that.
What can you do? Kids will be kids. They're going to listen to crappy music just to **** us off.
*edit: And there is still good music being made. You just have to look for it. For instance, this happened a year ago this week:
in another way - m b v - my bloody valentine - YouTube