On paper FM radio and even AM radio for that matter has pretty darn good audio when played on a decent radio, but you'd never know it because the stations pump up the compression so high it makes everything so loud it sounds like everyone is eating the microphones anyway, especially the CHR stations. So to me it wouldn't matter if they were all broadcasting dolby digital surround sound, they are still going to get into a contest to see who can out blast the other station. HD radio reminds me a lot of AM stereo. I thought it sounded really great but I could count on one hand how many people I know that even knew it even existed much less had ever heard it. Besides, finding an AM stereo radio was like finding a needle in a haystack. Nobody sold them. And shortly after I bought a stereo AM radio, my favorite AM station dropped the rock and roll and started simulcasting an FM station. the other two stations went to talk radio and all sports which was mono anyway.
What the radio stations need to realize is that the reason people buy satelite radios and mp3 is not because radio sucks. Its because radio STATIONS suck.