They have this to some degree in NATO, the problem is that you have to allow for some exceptions. For example, a design requires a special bolt head because the

They have this to some degree in NATO, the problem is that you have to allow for some exceptions. For example, a design requires a special bolt head because the standard one just won't work. No standard can be absolute and still allow for innovation. Military suppliers just milk this loop-hole and claim they need an exception even when they don't. Being able to evaluate when an exception is warranted and when the design could be altered to accommodate a standard would require enormous technical oversight.