I mean who cares if some guy running a convenience store or writing an email client thinks the world is flat?
Maybe we just need a small aberrant percentage of the population so there will always be a few people "shorting" the status quo for cash and occasionally preventing extinction.
We didn't need to be perfect to get to this point. Just good enough to beat the environment and the other meat sacks.
Predictiveness of a mental model is the the closest we can get to understanding reality.
It's not just this. It seems as though lying to oneself is so pervasive that it is likely a biological advantage.
Meaning not only is obsession with the truth not advantageous but it's actually disadvantageous while the opposite self deception is actually normal and highly beneficial such that this trait has been naturally selected to persist.