That is not true in most cases.Radio doesn't program for 24/7 listeners. It programs to people who listen in short bursts. That's how people use radio.
Yes, some listeners only "tune in" for their brief commute if they live close to work. But most tune in "for short bursts" over and over and over and over during the day. That is because they have to go to the bathroom, to lunch, to get coffee, to a phone call, to the loading dock, to pick up the kids, to go to the market, to drop off that Amazon return at Kohl's and so many other things.
The diary did not pick up that flow because nobody was going to write down all the things they did in the day that interrupted continuous listening. So we got lots of diaries with "9AM to 5PM" listening.... 8 whole hours. What it really turned out to be was 3 hours or less, in 15 different bits and pieces.
I was at a PPM seminar during the first year of the system. Arbitron did slides of one station that had over 20 different 5 minute to 20 minute bits in a single day with one listener. They used that as an example of how we had to look at TSL.
After the presentation, the Arbitron VP who did that "show" came over to me and said, "the example we used was your KBRG in San Francisco. You obviously figured out how to keep them coming back."
The listeners did not go elsewhere. They just could not listen for a while; can you listen while you are on a conference call,?
Actually, at work they do. They just have other things that interrupt continuous listening. Just as I interrupted this post to go brew some Alto Grande, folks can't listen non-stop... and never could. But that is the defect of the diary system, not of PPM and not of radioThey no longer "turn it on and rip the knob off." Unless they;re retired.
Lots of folks like curated and hosted playlists and that is what the PPM reflects.