I have noticed in the past year or two women are not wearing pantyhose with high heels, why is that?

Because yesterday I wore my high-heeled boots for the first time this fall since it just started to get chilly out. Since then I’ve been wearing flats. Today my feet and leg muscles feel oh so sore, like I just did a workout or something. So does wearing high-heeled boots make your leg muscles work harder and hence burn more calories when walking?? Is this why women who always wear high heels have toned legs?