That's why I said open-endedly optimizing. Obviously some amount of intelligence is beneficial to humans' survival, procreation and protection of offspring, but

That's why I said open-endedly optimizing. Obviously some amount of intelligence is beneficial to humans' survival, procreation and protection of offspring, but only to a point. If evolution tended towards ever greater intelligence, you'd expect to see the most intelligent individuals having on average a greater number of offspring. Instead, studies generally show a negative correlation between intelligence and fertility. This would instead suggest that evolutionary pressure on intelligence was not open-ended, but in equilibrium.