It gives them that classy hour glass figure
Most Helpful Girl
Why have girls stopped wearing corsets?
Likely the physical pain and long term adverse effects. Plus many gals may not be interested in appeasing one male's opinion or any male's opinion. The average American male is overweight/obese so I doubt most guys concern themselves about appeasing gal's physical standards. So perhaps some gals see no reason to endure pain and potential bodily damage for a fatty.
In my opinion in regards to your update there is a difference between physical pain and mental pain. As well as to me the pain from corsets is damaging while pain from dieting is self-deprivation to be healthy. For me pain from the gym is either poor figure resulting in damage or lazy people not getting used to fitness.5