Now, the big questions. The first one I ask before the "numbered ones" is ….'WHY?' How would it benefit you, your community, or your local broadcasters, let alone the industry. Please explain your position.
Then...
1) Do YOU own the equipment to enjoy this VERY hypothetical "switch" to digital?
2) How many people do you think do?
3) Bet you didn't know that while the government paid consumers to get "converter boxes" they don't even pay BROADCASTERS for any of the equipment they mandate for emergencies. ...thus, another question, How many AM stations would you like to see go dark? WE, the license holders would decide whether or not we would "go digital." An ANALOG new AM transmitter of just 5 kilowatts now tops over 50 THOUSAND dollars. It was 45 THOUSAND when I bought mine with insurance money in 2005. Do you really think that LOCAL stations, operated by people who live and work in your community are going to convert? Or ….will they just throw in the towel and sell their land? The government will NOT step in to assist broadcasters. There is no "bailout" for mandates for us....there is no "manufactured money" for us.
4)Even if a local broadcaster switched to all digital, Ideas like you suggest mean advertisers drop like flies, when THEY can no longer hear their ads which have kept their station on which they advertise and IN WHICH THEY BELIEVE for it's local content going. Your suggestion is more of a headstone for local AM radio than a suggestion.
5) Say all you want about compatibility with the current "HD Radio" receivers. They're dead or dying in awareness and availability. New ones are NOT out there, old ones were not well marketed, most owners of them don't even know what HD really IS, they think it's "High Definition."
Your scenario does not work for the FCC, (losing money they charge we, the licensees of stations) ...nor does it work for broadcasters, nor for communities with local AM stations, and MANY larger companies that only operate their AM stations because they already own them, and put them on the "asset" page...not because they WANTED them. They would alos likely shut DOWN many signals. It's a scenario best buried. NOW.