Addressing Serious Hacking Issues

It seem's sound to me, but I also have no clue of what mess they'd have to go through to implement that. I mean can you name any negative reasons that essentially hold it back? I doubt money is a big one, sound's like a good investment even if it's costly.

For one, they can't do it unless KMS does it, and KMS has no incentive to do it because KMS uses the KSSN to control their problems while GMS doesn't have that option, being global.

Two, it will be more stress on their hardware because instead of their servers just passively doing everything the client tells them to they'll have to evaluate every request they get to see if it's reasonable.

From a coding standpoint it honestly shouldn't take much, it's adding an "if" everywhere an "if" should be. Tedious but easy enoug a 2nd grader could do it.
It may be time consuming but the payoff is virtually infinite and this is the absolute most basic security anyone who's ever so much as thought of writing a client/server relationship should know from the get go.