Audio only DTV subchannels have been available on the UK Freeview DTV platform for several years, it's nothing new or radical.
But Freeview has been shown -- multiple times in this thread -- to be on a decline now. If that's the entire basis for your proposal, it is dead in the water.
I'm just proposing doing this in the USA (maybe only offering the top 20 radio stations in a market), if most radio listeners listen to the radio station stream and not the actual AM or FM (or HD) signal, a business analysis of the radio stations would raise questions about why the radio transmitter is being operated.
My idea would be a way, in a mostly streaming audio world, to still offer "radio for free" using equipment (ATSC 1.0 DTVs) most people have already.
It's technically simple, but (it seems) administratively complicated (convincing radio and DTV stations to do this).
It still does not address the reality that most radio listening is in the car and stream listening to stations is far below that. Perhaps David E. can bring in some statistics.
Any "business analysis" as you suggest would see that factor and come to the exact opposite conclusion to yours. I think you are perhaps presuming that streaming is a larger factor than it actually is.
And while I agree that the technical aspects are sound and have indeed be proven by Freeview, this is
not the U.K. and we have exponentially more stations, owners, and operators here. The logistics would be a nightmare and all it would take is one major station group owner -- either radio
or television -- to object and the whole scheme falls apart. (And if, as you suggest, only the top 20 stations in a market were included, you would have to get a buy in from Audacy, iHeart, Cumulus, or the other group owners on the radio side and
then also get a buy in from the major television group owners.)
Anyone know of DTV broadcasts other than in the UK that have audio only DTV subchannels?
I, for one, will be surprised if there are any, and there certainly wouldn't be any as extensive as Freeview. If the answer proves to be "no", would you then drop the idea as unfeasible?