I just heard Skrillex "Bangarang" on KYSR at 130 in the afternoon into Bob Marley. So it may be "alternative" but it's a Clear Channel station in a major market so it looks like Dubstep may have legs at commercial radio.
Also KAMP has been giving away tickets to Ultra and naming Skrillex, Afrojack and M83 in their promos- so I think what we are witnessing is a much greater acceptance of EDM across formats, which I think benefits the music as a whole.