You seem to confuse the life of a grad student and the life of a tenure track professor trying to keep their lab running. They're not the same, not even close. Unless you are/were one, or were married to one, or have actual data proving that academic professors spend the majority of their times in useless meetings, your argument holds no water. Comparing reading papers for undergrad courses or some masters experience in some compsci lab is just naive at the level where you are not even aware of a different plane of existence.

The biggest proponent of "you only need to work 9-5 and can still be a successful professor", Cal Newport, himself walked back those statements somewhat after he started going tenure track.

I'll give one corollary though, which is that there are some very successful professors who actually don't work that hard. I am friends with one; they're just simply not human. I remember reading from the same textbook with him and he finished the pages 3x faster than me. So the only way you get away with regular life in academia is to have a super human brain. The rest of us have to compensate by putting in the extra hours. It's not healthy, at least not for me, which is why I chose to leave. But many do it. And continue to do so. It's arguable if their lives are worse or they don't mind it, but it's not arguable that they are just morons who don't understand time management.