Well, here's the thing: teen pop acts aren't nearly as dominant as they were back in the late 90s. Not many people outside the tween demographic give a rat's ass about the Miley's and the Jonas's of the world.
But back in '99, Britney, Christina, the Backstreeters, NSYNC, and the like were all over the place. They made an impact worldwide, sold through the roof, and dominated the charts. Their influence on pop culture was far grander. Not to mention, they made far better music. As a fan of pop music, and as someone whose listened to both Miley and the Jonas Brother's more successful albums, their tracks don't hold a candle to the best of the 90s era peeps.
To put it bluntly, pop music sucks major ass these days. And that's why nobody bothers to go after them, because they're pretty irrelevant in the grand scheme of things.