Preserving AM radio is important for a few reasons that go beyond cars. AM broadcasts have exceptionally long range with relatively little power. Transmitters and recievers are among the easiest circuits to build completely from scratch, as there is no arcane or proprietary knowledge needed to decode the signal. For these reasons, maintaining AM radio infrastructure is an important insurance policy in case of natural disasters or other major public safety events, even if it is something 99.99% of people will not interact with on a daily basis.
I advise people to get a shortwave receiver. They're inexpensive, and are actually even better in emergency situations.
In almost every car you can run the radio off just the battery without the engine and most people have at least one radio in their home besides their car. (If you don't have one, you really should and they're only $10 on Amazon.)
> If they really want to keep AM radio viable start a public awareness campaign about its importance and make radios available for free.
Public awareness campaigns won't pay the bills for radio stations. This is about ensuring there is enough of a market for AM radio stations (since most radio listening is done in the car these days) that they can sustain themselves from ad sales so they can fulfill their public service function in the event of an emergency without (direct) government subsidies to keep the lights on.
https://www.amazon.com/Goodes-Transistor-Headphone-Reception...
Fast forward to the first emergency that actually needs this and you're gonna see a bunch of asphyxiation deaths from people running their cars in the garage to listen to the last AM radio they have.
If they really want to keep AM radio viable start a public awareness campaign about its importance and make radios available for free.