Has any one ever asked why the U.S. dose not use metric and others do but the pitch is different?

Well lets stop and think about this a little. ------------------------------ The answer is so simple you see if I was in combat and I lost a screw for my weapon then I could take one from a enemy soldier and  fix my weapon and keep on fighting. But if your screw did not fit my weapon I would also have to stop fighting. And that my friends is the reason there are different pitches to the threads