If it were truly a simple hack, it would already be done, since the health benefits are well known.

Getting these countries to stop burning leaded gasoline sounds like a fairly hard problem to me, just from the fact that they keep doing it. A sibling poster mentions how many problems have had simple solutions, like vitamin C for scurvy, which is true in the abstract but they all took quite a lot of fighting to implement.

Now, I doubt that lead is a significant factor here. But even if it were and it could be demonstrated, would it really be "simple"?