Ties where proceeded by the "cravat", which in turn was based off the neck wear worn by the Croats light cavalry. They where scarves mostly for practical purposes, to keep dust out of the rider's mouth and eyes like you see in Western movies with bandanas. The French saw the Croats, thought the outfit was neat, and copied it for fashion reasons because that is what the French do. The fashion died off, then made a resurgence with a new twist: it was now incredibly fashionable to tie your cravat in impressive ways. Then the industrial revolution hit and everyone could afford a fancier cloths, so everyone wanted fancy neck-ware for themselves. But they also wanted it to be easy to put on and last all day, so they designed them long and thin so they would be easy to tie and wouldn't come undone. Thus the necktie was born!

In other words it's all because the French are poncy tossers.