you might be right to an extent, but that doesn't explain the gap going from 64gb and skipping the 128, and straight to 256. if apple operates their storage tier purely on what you said, with the price gap difference for manufacture side for adding additional 64gb is less than 10 dollars, with apple's purchasing power, probably even cheaper.
as for vocal minority, the butterfly keyboard complaints started on reddit and forums like this, then gain tractions through main stream media, and finally made its way to the oscars. don't discredit the vocal minorities.
ofcourse, my guess work is just as observational as yours, after all, guess work.