It’s just a name for one legacy-labeled stream among countless others on the Net. Radio’s boat-anchor legacy is called “range” and “coverage.” On AM and FM, those are limited to a city or region, and to legacy receiving devices mostly used in cars, where more and more sources of content (Apple, Pandora, Spotify, SiriusXM, et. al.) are appearing on the dashboard. The quality of legacy radio electronics is also limited to cheap available chipsets and by the fashion of concealing antennas, which makes reception even worse.
This latter, after looking at my car, certainly seems true to me: Bose, or whoever made this auto system for them, might have spent maybe 85 cents on the AM section, and the antenna is more or less hidden among the rear-defroster wires, good for aesthetics, not so good for reception.
But this I did not know, though I shouldn’t have been surprised:
AM won’t even work in all-electric cars, thanks to interference from computing machinery. That’s why it’s not included in Teslas.
Nissan will sell you an AM/FM/CD system for the all-electric Leaf, but then it’s probably got a lot fewer sources of interference than the Tesla.