I need to do a longer analysis of this, but here's the short version: after several quarters of public radio stations (mostly news/talk) beating the usual ratings-winners (also mostly news/talk), those commercial news/talkers are getting the message, and they're changing their programming.
At the moment, I'd say it's still a clumsy, awkward change...not one to soon draw away pubradio fans. But the beast has been awakened, and it's not going back to sleep. Sooner or later commercial stations will start tailoring their product to better compete with public radio's offerings, and that's a serious problem for public radio.
Because public radio, by and large, is not good at competing. Even in cutthroat markets there's still a lingering geniality that (stuffy British accent) we're all good sports here, chap. Plenty of listeners to go around, you know?
Except it's not true, and if commercial radio steals back all those listeners pubradio has fought for, a lot of pubradio stations are going to find themselves deeply in the red. They've come to rely on those listeners to generate fundraising and underwriting revenue.
Here's the evidence: KIRO-AM in Seattle took note that KUOW topped the ratings for two books in a row, and now they're (pretty substantially) shifting their lineup. Anecdotally I can tell you that commercial radio in Boston has not ignored WBUR's rating successes over the past year or so, either...and there's been giant holes opening in the schedules at all three of our big news/talker commercial stations (WTKK, WRKO and WBZ). Just this week it appears that our big sports/talker, WEEI, might also need a new morning show as well. (or it might be just a stunt, who knows?) Still, change is a afoot and I would lay good odds that at least one of those three stations ends up with a more "public radio" sound at the end of it.
Ya know, all that speculation that Christopher Lydon could end up on commercial radio suddenly doesn't seem so crazy after all...