> code with a high cognitive load keeps mediocre developers away.

That's true and it's a positive thing but the downstream consequences are often painful. We had a c/c++ project with complex memory management and heavy multithreadding, written that way because the superstar developer could handle the cognitive load and found the assignment intellectually challenging. That was great until they left for the next job.

We were left fighting a codebase with a big cognitive load, so we were desperately dependent on hiring more superstars just for routine maintenance. We eventually concluded that this wasn't a sustainable model and rewrote the system in plain old python. Much happier now.