Arch support in a shoe seems to be important these days. I recently read an opinion that Vibram five-fingers shoes might not be as good as once thought, partially due to lack of arch support.
People used to run and do all activities without shoes. Even recently, Converse (presumably without arch supports, same as today) were an official shoe for things like basketball. Our feet are not formed with shoes in mind. Shoes were an afterthought.
So, why is arch support so important? Is it because our feet have become accustomed to them and are now incapable of safely walking / running 'the natural way'? Is it a marketing gimmick? Or something else?