Hubby and I collect WWI & WWII items. The WWI uniforms are TINY...oddly so (we have quite a few). I'm 5'4"; 125 lbs; and can barely get my arms and shoulders into the mens' uniforms.
Occasionally, at a very large show we will see a larger-sized uniform; they are so rare they command $1000, or so.
Even the larger sized WWII uniforms are more expensive, as most are what we would consider a small or medium today.
HOWEVER, I have WWI & WWII Red Cross nurse uniforms that fit me perfectly. I think that mens' frames have changed far more than those of women.
Interesting. Could be that men's diets have changed more than women's ... or that men, having a great potential height (on average) than women, show the effect of dietary improvement more.