I think that’s where we differ in analysis. If you had a charismatic leader who was snapped and another that was ruthless who wasn’t snapped, even if you lost 50% on both sides, it could greatly cause an imbalance.
As for a genius or such, it could set progress back by decades or more or they could have produced something that had a positive effect to change the course of their race.
First point: fair enough, I see the flaw. But then we’re changing to a more ethical dilemma: does a charismatic person deserve more chance to live?
Second point: with half the population left, there is more time to solve things (caused by humanity). Global warming, for example, will likely be solved by just the snap alone.
Maybe he could have made it that every female can only bare 2 children, that would gradually reduce population. But that would put a huge strain on the younger generation to take care of the elder.