[Mz]

That's been discussed here before. I was kind of pissed on for agreeing with it. After most of the smoke was over and the party disbanded, someone (thaumaturgy, iirc) pointed out that cars became more aerodynamic because of the higher speeds of highways, and that might be the missing link as to why interstates and cars helped kill men's hats. Before that, cars were boxy enough to still wear a hat in one.

Edit: Having now read the high heel article, they aren't 100% correct about heels being useless in the muddy streets of the era. Staying up out of the mud was part of the point of heeled boots of the three musketeers type era.