For example, I’m incredibly confused about how you’re supposedly to measure liquid laundry detergent with the cap. At least the kind that I have sits on it’s side, so if you measure it with the cap it just leaks everywhere and makes a mess.
Or at my parents house they have a bag of captain crunch berries that has a new design, where instead of zipping along the top of the bag like normal, it has a zipper in the front slightly beneath the top. That way when you poor it you can’t see what you’re doing cuz the bag is in the way. Like what the heck who’s idea was that?
I just measured my usual toilet and while the hole is more squarish than the round one in the picture, the 16.5 length is about right. I don’t have any problem. I’ve got average sized junk, and have maybe a slender to medium build.
Maybe weight, whether one is a ‘shower’ vs a ‘grower’, or some particular anatomical proportion play into it, I don’t know. Maybe how far back one sits is key. Maybe people vary in their butthole to junk measurement. But I don’t think this is as universal a problem as OP thinks. But, hey I’m all in favor of a longer toilet standard for those for whom it is.