Oh, people still tune in, hoping for something better, but they don't stay with most stations because there's nothing special to keep them. Some people still use radio for background music because it's cheaper than satellite, but the evolution of streaming will likely eat into those numbers.
There are exceptions. There are still some very good radio stations out there, that are involved in the community, and serve their local listeners well. You'll generally see them near the top of the ratings. Unfortunately, too many of them have lopped off live mid-day and evening talent as a "money saving measure". Revenues decline, and corporate demands even deeper cuts without considering the thought that the cuts actually cost them more revenue than they saved.
TSL has been on the decline since the '80s - significantly before computers and the Internet were widely available. Now, the PPM, with its miniscule sample and inability to differentiate between active and passive listening, is spewing out more numbers.
The corporate reaction? Fire more jocks. Make the programming even more generic. More syndication, shorter playlists, less talk. Oh, that's just what people say that they want. Gee, is it possible that people tune around so much because what they're hearing is too repetitious? Gee, I've never heard that comment from a listener - or, more likely, a FORMER listener.
But, carry on. You obviously know best. How's that definition of insanity go, "Doing the same thing over and over, and expecting different results?"