That's a bigger pain in the ass than Spotify.

So, my Galaxy S4 Mini circa 2013 had a built-in FM tuner. It required wired headphones to work because it used the headphone wires as the antenna, and there was some reasonable little app to use it, like it was a feature in Samsung's media player or something.

My Galaxy S10e circa 2019 also had an FM tuner, that also used headset wires as an antenna. Samsung provided no software support for it at all, the only app I could find that allowed you to use it was a long unmaintained third party app apparently intended for Southeast Asia mainly geared around some central aggregation service that maintained a database of radio stations so it could compare your GPS coordinates and a genre to automatically tune the radio. You could push the "rock n roll" button and it would look at where you were and go "Here's the three rock format stations in your area." That service was long since gone so it worked in a badly made fallback tuner mode.

My Pixel 10 Pro does not have a headset jack, or any FM tuner hardware built in. I don't think iPhones ever had that capability, I think it was peculiar to Samsungs, and it's gone now. So even if you used to know how to listen to FM radio on your phone, you can't anymore. So you need another device, you need an FM radio in addition to your phone.

People would rather chew their hands off than carry a separate radio around, if they can find one. Have you noticed that the market for stereos is basically dead? The likes of Circuit City and Best Buy used to have entire departments for stereos, you could get boom boxes, bookshelf units or component stereos at a variety of price ranges. That's ALL gone now except the very high end. Hell even the PC speaker market has taken a dive, Logitech still makes them out of force of habit, kinda like joysticks, but you're supposed to wear headphones as a PC gamer now. You buy a sound bar for a TV or a bluetooth speaker for your phone, THAT'S IT.

For most of the public, FM radio is the button on your car infotainment screen you never push, next to the other one you never push labeled AM.