I'd think that what'll dictate whether OTA broadcasting continues in the not too far distant future is whether or not there's an audience for it any longer.

The younger generation(s) tend not to listen to radio at all according to the surveys. They like to carry their own music with them so they can hear what they like, when they want it or, maybe, listen to internet radio at a stretch.

Hell, they don't even wear wristwatches any more - they have a smartphone if they want to look at the time.

I have a strong expectation that OTA broadcasting will continue for another few decades but eventually, once Wifi soup is everywhere, it'll go away because it's no longer relevant or desired by the audience it was intended for. Why bother with antennas, electricity bills for transmitters, FCC licenses (for those who are legal,) broadcasting rules and stuff like that when all you really need is a net connection and determination?

It'll be a sad day for RF broadcasting when it happens but on the other hand we'll be seeing a day when content will, once again, be king. Why listen to thirty minutes of more crap you didn't choose when you can listen to whatever narrowcast you want? What's good will thrive, crap will wither - the days of captive audiences has passed.

And, unless some re-purposing of the system happens, a broadcast licence won't be worth the paper it's printed on.

You may think it an unlikely scenario but you should ask the typewriter manufacturers, small print shops, Cumulus, Clear Channel, manufacturers of old school radios, recording companies, movie companies, short wave broadcasters, newspaper publishers, Encyclopedia Britannica, publishers of skin magazines, totalitarian governments, intelligence agencies, American workers in IT, etc., etc., whether or not they expected business to be so screwed up as a result of the 'net's rise.

I love radio but I never forget that most people want content, not the medium it's delivered over. They could care less about that.

Lee