A hash, if it is one, isn't "one to one", even though it could be possible for you to find a key from an ID. Maybe an automated search process that excludes IDs longer than 10 and shorter than 5 or something. The ID algo has to be reversed etc. But we have no direct need of it currently which means we aren't ready to put in work and time in it right now. We make cheats, not keygens (primarily). There are at least two easier ways to do it too.