Right so you're getting into deeper questions of what intelligence really means, and whether our measurements are meaningful in practical terms. Even if it was possible to genetically engineer humans with much higher IQs (and that is yet to be proven), there's still no evidence that those hypothetical supermen would end up ruling over us or having more children or whatever.
I didn't do good at school but i had many friends! I never felt i was less intelligent than my friends which make me question the IQ score thing.
My Dad has high IQ (135) and he's a mathematician.
So how did i inhert low IQ? My mom's score is average at best, 102.
I've sold 3 companies, i am married and I've managed to be quite wealthy.
You don't need to posses high intelligence to survive and reproduce in this world that's why it's not selected for.
We don't walk out of womb and given a puzzle to solve where if we fail, we are instantly killed.