That could ultimately leave XM and Sirius out in the cold, at least in their present form. They could still compete with better content, but as I understand it digital radio would be free, with very good SQ. I'd like to see it, although one wonders how long it would continue to coexist alongside FM. FM is very entrenched, much as NTSC TV is- even with an FCC mandate the broadcasters are dragging their feet on the transition to digital.
I guess it's not terribly expensive to inplement, but I wonder how much a reciever will cost? You'd need some installed base, or at least the perception of financial potential, before it'd be worth it to broadcasters. Of course, there's a chicken-and-the-egg factor there; consumers would want some content before buying a digi-tuner.