There is nothing "failing" about radio. It is not a growth industry, but hardly "failed".DE, you constantly describe a broken and failing system to me. The jargon, insider knowledge, and obtuseness of it all make it clear why the product is what it is. everything is very convoluted. Almost every common-sense avenue is avoided in favor of arbitrary industry standards. Little room for experimentation despite the declining value of these stations. Weird.
"Insider knowledge" is the stuff that makes us know things like "95% of all in-home and at-work listening is in the 65 dbu contour or greater" and stuff like that. It is called "experience".
In your case, as an example of your lack of "insider knowledge", you are using statistics that neither the ad industry nor the radio industry use.
And "insider knowledge" is what allows us to know that in larger markets, small local businesses can't afford mass media. So radio has to focus on chain stores, consumer brands and services. Most of those use ad agencies or have in-house media departments. And radio stations have to deliver a product that those advertisers want, within the demos that they wish to buy.