S/M and M/L Band legnths

How come the only watch that comes with two different band lengths is the sport watch. I know this isn't plausible for the metal link band, but extra links can be aded to those and apple has release extenders for those bands. I'd like to see a s/m and m/l size for the wool and leather bands because one size does not fit all, and everyone does not want a gaudy (using this loosely) 42mm.