No one really know why we even have foot fetishism or ANY fetishism. What they do know is that apprently the attraction, that is, the association to the object (or behavior, etc.) begins in childhood, but there are some other kind of factors hardwired into the person that need to be activated. In other words, someone may have the potential for fetishism, but never encounters the factors in his life to bring it out. Some people may be surrounded by fetishistic objects or situations (a family-run shoe store or cobbler shop, for example) but a fetish never "takes" because something is lacking within him. And in others of us, it seem a part of our nature that we can't explain. That's why these things are so hard to get rid of. I remember seeing on Oprah years ago the story of an arsonist who, as a child, was molested by a family friend, a fireman.
Foot fetishism used to be associated with subconscious feelings of self destruction and low self esteem, but now psychs seem to think that attraction to a woman's feet may subconsciously be related to feelngs of safety, security and comfort: the foot fetishist as a child probably spent a lot of time on the floor or at the feet of the mother and felt the most safety and comfort there. Those associations were shot through and became perverted by the grown-up's puberty cathode ray tube into a fetish or partialism.
I've read somewhere - and I DON'T remember where, darn it, I think it was "Psychopathis Sexualis" - that 80% to 90% of men have a fetish or partialism, and of those, 80% to 90% percent could be almost evenly split in half, one large percentage being into transvestism, and one large percentage being into something having to do with feet (attraction to feet, interest in stockings, shoes, etc.) If these numbers are correct, then most men have some kind of fetish, and a large number of them are into cross-dressing or feet. So having a fetish is more common than we really expect in American society, and what we have is fairly predictaible. If a man isn't into a woman's shoes, he probably want's to GET INTO them....