That is not necessary true.

There are at least 4 different types of microphones. Condenser which does in fact form part of a capacitor, dynamic which is effectively a linear generator (coil attached to membrane), ribbon which is a change in resistance as a small ribbon flexes and piezoelectric which is some black magic witg crystals

Sure, that's why I wrote most microphones.

There are also some exotic principles like laser or radar microphones using interferometry.

https://en.m.wikipedia.org/wiki/Laser_microphone

https://ieeexplore.ieee.org/document/7808865

Fascinating. Is there a book about the history of microphones?

I find this to all be in the realm of "I don't believe you that any of this works at all" if I didn't have a lifetime of experience with the fruits of successfully-functioning microphones.