I have a theory that if they had named the 12 mini just "iPhone 12", people would've bought it so much more because it would've appeared as The Default iPhone. Not sure if so many bigger variants would've existed in that imaginary world though.

I have no research on this of course. I just have an anecdote that my mom didn't even consider the mini (and just bought the regular 12) even though a few years back she did complain how big all the phones were. I guess an average person just gets used to everything and aren't as nit-picky on all the details and ergonomics as myself.

I still long for one-handed flagships. Maybe I'm just a weirdo for whom 5" phones from a few years back (e.g. Pixel 1) were perfectly operable with one hand. For a lot of the population those phones were already two handed devices in most use cases I guess? Couple this with how phones are the main computing and media consumption devices for most people nowadays... why not have it remarkably bigger I guess.