Have you actually got any idea what goes on in a front row? That's just scrums alone, before you bring into it the rucks, mauls, line outs, defensive positions, game awareness, protecting backs when they get tackled etc.
It's not simply a case of being stupid enough not to get your head kicked in in a scrum. Props also require the ability to pass, and also to make decisions and create gaps often in far more confined spaces than a fly half. The only one of the skills you listed for a fly half that a prop doesn't require is kicking form hand, and that's because if you kick in close proximity to the opposition forwards they will pick the ball up then simply kill you for being a fool.