This is something I had been wondering about - if all Cumulus has to sell or donate is the frequency license itself, don't they really have nothing to sell or donate?
A license isn't nothing, but an AM license is usually pretty worthless.
There is no audience or format to transfer, so there's really nothing.
How many times have successful stations been bought and nuked by the new owners? It's pretty common. Operators buy stations to carry out their business plans and missions. Those are often not the same as the previous owner's.
If somebody had an idea for something new, wouldn't it make sense to wait for them to 'turn in the license' and then apply with the FCC for the opportunity to broadcast in the public interest from scratch? It wouldn't come without costs - FCC fees, engineering plan reviews, as well as the physical plant, but would that be less than what a broken down media company might be asking?
Absolutely not. Remember the quote, "A bird in the hand is worth two in the bush?" If you have someone willing to sell you a license for cheap or otherwise donate it, the license is yours. Waiting for an auction means you're spinning your wheels going nowhere until the FCC decides to open up a window. It also means you could be outbid for the license. Plus, like you said, you have to do all the engineering and, potentially, building out. Waiting for an auction is a lot more expensive and offers no guarantees.
It is disheartening to read radio professionals advocate for shutdown as opposed to trying something new.
If you could get 560 for a song, what would you do with it? How would you make money off of it? The unfortunate reality is that you can't make much, if any, money off of AM radio anymore. It's 100 year old technology, and it's had a good run. Every technology eventually outlives its usefulness and dies. A handful of people are still making money off of buggies and whips, but they're few and far between.
This is I think a harbinger of radio overall.
At some point, FM will also die. It's part of the lifecycle of technology. Radio is always going to be around, but that doesn't mean people will consume it the way they currently do or will see it the way we see it today. I have a 21 year old niece, and, while she does occasionally use over-the-air radio, she would also consider selecting a genre or curated playlist on Spotify to be radio. Radio is evolving and continues to evolve.