Yes this is in my thoughts as well, as do 3:2 sensors, I shoot quite a lot of vertical shots then crop to 5:4, on a 4:3 sensor you just loose a little top and bottom, but on 3:2 sensor you lose a lot more and if you are cropping into the image as well, then the resolution decreases rapidly.
I do think though that a GFX plus a Leica Q2/Q3 makes a nice (if expensive) camera combination.
I first programmed a computer on punched cards, so a mobile phone was well into the future.................................