I've held this belief for a long time. We tend to think we have the brainpower but we just need the understanding. I think it's far more likely that we have nowhere near the brainpower required to understand the true nature of reality.

There is an argument to be made that there could be a phase transition when it comes to the ability of understanding things.

When you manage to write down your thoughts so future generations can build on prior work, and when you manage to formalize problems by abstract notation (math), and when you gain the capability of breaking down complex problems into small solvable chunks, then maybe, and I want to stress maybe, there is no limit to understanding things.

On the other hand, there also may be problems with irreducible complexity, so it really could be either way.

Perhaps, but I'm partial to the interpretation that we simply don't understand quantum mechanics well enough to explain it to, if not a dog, children in high school.

Note that we do teach classical mechanics (to a point) in high school, even though it was the cutting edge of physics at some point.

i've thought about this too. When the only tool you have is a human brain you try to solve everything with a human brain.