AM transmitters / receivers are far easier to construct than FM ones, though. If I was in an emergency situation where I couldn’t communicate with anybody I think I might be able to at least make an AM receiver, even if there aren’t very many components around… But I would need a reference to have any clue how to approach an FM one, and you’d definitely need more components available. Frequency modulation is quite a bit more complicated. If you want to transmit, CW is probably your best hope?

Realistically, though, almost anybody in an emergency situation is doomed if the only thing that would save them is building any kind of radio. It’s not a skill set that most people have… Which I guess is why you might advocate for everybody’s phones to be able to act as FM receivers in case that’s the best way to get an emergency broadcast, because then they would have a device that’s capable of it on hand. You’re probably better off if you have a dedicated emergency radio, especially if you might lose power for an extended period of time, though.