The issue I feel is not that phones are too big but that niether Apple nor Google have bothered to adapt their OS to take into account variable device dimensions.

I wrote a whole piece on it previously but the gist is that if manufacturers and developers took into account device ergonomics then there would be (and shouldn't be!) any interactions outside the bottom third of the display in portrait.

https://medium.com/@carlst-james/ergonomorphism-next-big-thing-in-ux-f895495051ed

There is probably a seperate conversation to be had about phones transforming from digital swiss army knives to addictive black holes of content but I'll save that for another day.