Arbitron ratings indicate that fewer educated listeners are tuning into broadcast radio at work. Podcasting News ran the story I found and pointed out that those listeners using the Internet for music at work has risen from 12 percent to 20 percent in a single year.
I recently posted about how one newspaper's efforts to go hyperlocal were failing because it had not taken the time to intimately know the market in which it was competing. This is less of a problem for broadcast radio stations, which generally have local personalities hosting their shows. In addition, radio stations have done a better job of moving online. The question is, can they provide enough local information to keep people tuned in.
Local traffic reports and lack of true Internet radio in cars, will keep those without satellite radio tuned in over the short term, but at work, where people want music as background noise and don't (or shouldn't) pay that much attention to the personalities, will be a much bigger challenge.