Because electronic music is being accepted by the mainstream. Mainstream is what sells. Doesn't matter how hard a band works. If they don't get on the radio there isn't a whole lot more they can go up.
This is false. Take Brand New, Circa Survive, Taking Back Sunday, Bring Me The Horizon, A Day to Remember, Motion City Soundtrack, Say Anything, all of these artists have huge followings. While they may have a song or two that appeared on the radio at one point or another they haven't in 2012 and these bands are still extremely successful financially.