AM is not dead, if you've ever lived or visited outside of the big metropolitan areas. It's normal to have a radio on the kitchen counter tuned to the local station, for gossip, local news, talk, and ads that are actually relevant to you.
Is AM a genre of radio or a transmission method, or both?
This kitchen radio is common too in the UK but the radio would be FM at the least, more likely DAB these days. BBC Radio 4 or '5 Live' nationally and the BBC have dozens of local radio stations all over the country. All talk, no music.
Kind of both. It's a transmission method (amplitude modulation) that's very lo-fi which leads to it rarely being used for music, which dominates other radio. So it ends up being talk shows, sports, news, traffic reports, etc.
"very lo-fi" is pretty relative... FM offered higher quality audio, but that came mostly from the fact that it was not as prone to interference. (And yes, it was stereo instead of mono, but I think stereo AM became a thing eventually.) Other than that, if the station you were listening to was not far away, there wasn't really any difference in perceptible quality _if_ you had a decent receiver and antenna, which most people didn't. It was cheaper and easier to make an FM radio that sounded good compared to AM.
If you tool around the HF ham bands at night, sometimes you will catch a couple of hams conversing in AM near the top of 40 meters. The ones that have spent some time tweaking their audio and transmitter sound like they're sitting right next to you. Very crisp and clear, especially next to single side-band!
If you want to get a feel in real-time, visit a site offering WebSDR[1]. Look for a receiver in the US and tune between 530-1700KHz in AM mode. Note that reception will vary based on time of day [2].
Amplitude Modulation (AM) is a transmission signal format. It works by modulating the amplitude of a chosen carrier wave (the frequency you tune in to). Your receiver filters out the carrier wave and leaves you with an ordinary sound signal.
It is also a genre, in the sense that it is almost exclusively used for news and talk radio. This is because the bandwidth available on AM bands is not really suitable for rich content like music.
One leads from the other: the nature (transmission range, operational costs, and quality… or lack there-of) of AM radio in North America led it into rural-focused, talk-only (and eventually “conservative”) programming - and sports (just like how BBC Radio 5 is also AM, not FM).
> AM is not dead, if you've ever lived or visited outside of the big metropolitan areas.
Decent amount of AM in Toronto, Canada. Mostly talk shows and lots of sports broadcasts/discussions. 680 is handy for news/weather/traffic as their format is to do a 'loop' of major topics over a period of 30 minutes.
In Greater Toronto area, I like 1150AM which used to be sports station (opex galore) (and an oldies/community radio station before that), but in a cost-saving measure, now just simulcasts a subscription (!) business news TV station (BNN Bloomberg).
Even in the big areas. KFI-AM and KNX-AM are still huge in Los Angeles, for example. Both have FM simulcasts but I've gotten KFI-AM in Arizona and Nevada no trouble, and the KNX FM simulcast in particular has odd coverage gaps.
The counterexample in LA is KABC-AM which is a shadow of its former shelf.
.. and of course, baseball.