I don't think it's that simple. Competence isn't always used to get food. There are a lot of different skills and kinds of competence, and a lot of them might get you singled out.
It's often the smartest kids in the class that become the target of bullies.
Also intelligence often tends to question the social norm, and that's a recipe for getting singled out.
This post really strikes me as being a (rather pessimistic) perspective on life rather than a factual description of the competence level among humans.
Consider these two statement, which are both true:
Everyone is free to hold the perspective that, since aerospace engineers are messing things up on a daily basis, they're incompetent; or that despite the fact that aerospace engineers do a lot of mistakes, they've been able to send rockets to the moon, which is quite an achievement.
It's important to look for mistakes but it shouldn't take over our perspective on things.