TV figured out that national shows trumped local ones pretty much always. That is why in the late 50's we go The Tonight Show as a national daily event and then we ended up with Wheel and Ellen and very little local origination outside of newscasts.
Radio, nearly everywhere else in the world, became national or, at least, regional. Local could be inserts (like TV does with the morning blocks) or not done at all. Today, many national radio stations use the web and messaging to handle local aspects. In those nations, we find "national quality" hosts and radio services right down to the smallest market.
Yes, TV figured out that national shows trumped local ones, because the networks (and the production companies/studios) could afford big budget productions, while local TV could not.
This has not been the case with radio...at least here in the US. The number of "national quality" hosts and programs was few and far between, and that's still largely the case. For most of the history of radio, the local host or show ruled. What has happened is that the local content has been/is being eliminated, but it is not being replaced with the national quality stuff.
Yes, there are people like Seacrest, and regional talents (Big D and Bubba comes to mind), but overall radio is nothing like TV. A lot of that comes down to - again - budget. We've been in a "Golden Age" of television for quite some time now. Cable outfits like HBO and streaming services like Netflix and Amazon Prime have figured out that big budget, high quality content will bring in more than enough revenue to cover the enormous costs of something like Game of Thrones, and the traditional networks have had to keep up, throwing more and more money as viewers demand higher quality content. Local stations get the benefit of being able to sell that content to viewers and advertisers. No, the local morning show on your NBC affiliate might not be national quality, but they can point to Chicago Fire or Law and Order and say "we've got this stuff."
The companies that own most local radio stations are not paying a premium for high quality content. They're thinking about how they can do things as cheaply as possible, so instead of a national-level talent, you get a guy (or gal) who is doing an afternoon show on a half dozen stations or more, while tracking weekends, scheduling music, and wearing a couple other hats while getting nowhere near national level money. Meanwhile, streaming services have stepped in an said "we'll play the music you like, tailored to your desires, and you don't have to listen to that underpaid DJ jabbering on about some national contest you'll never win before going into a 10 minute commercial break where some local car dealer yells at you."
National quality radio down to the smallest market sounds like a great idea. iHeart, Entercom, and Cumulus ain't doing that.