You're right about one thing, I haven't seen many women in public declare they have a foot fetish, and in the porn I've ever seen, it's always lesbian foot worship if it's in a non SM relationship. I think another idea of that is women's feet, while not just better taken care of, are more often than not visible to everyone. Women can wear strappy high heels all the time, where men are usually forced into tennis shoes and loafers, with only flip flops and sometimes sandals a release from that. The more visible the object of affection, the stronger and more prevalent the fetish becomes, so women don't have as much to look at.