Feature phones are not old-school mobile phones. They're crippled smartphones. As near as I can tell, nobody actually makes good old, dumb, cellphones anymore.

I'm not sure that is correct. Granted, there doesn't seem to be a lot of them anymore, but they're not all gone. Here's a list of dumb phones made in 2021-2024 running an "unnamed OS": https://www.prisjakt.nu/c/mobiltelefoner?197=2024%7C2021&438... (sorry, Swedish product comparison site, but the phones should be possible to search for elsewhere on the web) I don't get the impression they are crippled smartphones.