I know they have never ridden kei trucks. I'm a 175cm Japanese and its seat and space is obviously uncomfortable. It's fine for the purpose (carrying farm equipment and other stuff, drive max like 10km at 60km/s) but not comparable with richer trucks. Looks better to compare with 90s Hilux.
I'm a 185cm non-Japanese, and kei truck seat and space has been just fine for me. You can't recline the seats obviously, but that's not why you're in the truck