i kind of understand, but that's a whole bunch of generalization. I can however say a little bit. Unfortunately, the Japanese (men) have not grown taller over the past 30 years (171cm). (Nor women) On my end, i'd criticize far more choices of veggies in Japan rather than meat which i don't find to be severely lacking.
5' 5" is more like the average of peoples even shorter than the Japanese. Those are almost the shortest by the world's standards. Quite a few Jp men, and while I am not very familiar with this population, easily go a bit over the range of 170cm. But, yes, i've seen quite a few shorter men.
The shortcomings of JAV is more likely about JAV trying to please dorky/ugly audience by using actors who look like them. However, i am not sure if white porn girls (or mixed blooded Japanese-white or latina or whatever girls) typically only fucked ugly guys in JAV.
I think over the years JAV has evolved/changed, too, because they can no longer literally abuse women but forcing them to eat poop/get fucked by a whole bunch of guys/other borderline illegal behaviour (or actually illegal). Maybe when they now tend to go easy with women (and essentially pay more respect to them), things are changing.
(don't really quote me on this)