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.
I think popular is very situational though.
For me I see a lot more dynamic than condensers but I guess if you are talking about what is in like every single IOT thingamabob then you might be right there.
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.