Absolutely right.

Just because a few driven individuals can survive Navy SEAL selection (BUD/S) doesn't mean that BUD/S is the optimal practice for everyone to have a productive, balanced, or happy life.

Some people do fine on 60 hours a week. Some people burn out on 40 hours. Some people sleep 5 hours a night. Some people delude themselves into thinking that 5 hours a night is all they need and then sleep 14 hours on Saturday.

This article is good insofar as it's one man's exploration of the question. But everyone needs to figure it out individually - there's no one-size-fits-all answer.