People want to believe we are capable of anything as humans

A depressing thought I've had is that maybe we will reach a point where we can go no further due to biological limitations. Think about monkeys, they have primitive tools but are effectively stagnant.

It's an objective fact our progress has slowed

https://www.technologyreview.com/s/601199/tech-slowdown-thre...

A monkey can't understand advanced mathematics. What if there are certain things about physics and the universe humans will never be able to grasp because we are simply too stupid as a species?