system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are shoe sizes separated into men and women's categories instead of one neutral scale?

I was at the mall today and went to a Footlocker just browsing shoes and then left without getting anything. However, in another section of the mall there was a Women's Footlocker selling the exact same shoes as the other Footlocker. I've bought women's shoes of the same design for myself in colors not available in men's shoes before (I'm a guy) and they fit the same exact way that the mens shoes do (gotta buy 2 sizes up in women's shoes though because I'm in the US and not sure if it's the same in other countries). So why hasn't the US shifted to one scale if both men's and women's sizes overlap with eachother?
gpt
Men's shoes are not only longer than women's (higher size number) but also wider than the length would strictly indicate.  In the sizes you'd ordinarily buy women's shoes, you probably wouldn't notice - but a man with size 12 feet would probably feel very pinched if he tried to wear a size 14 woman's shoe.