balance: the perennial virtue of the under-achiever
https://sloanreview.mit.edu/article/top-performers-have-a-su...
While balance isn't required for happiness, I know many imbalanced, unhappy and underachieving people.
Second, if we consider "achievement" to be measured by income I have far better work-life balance as a software engineer than the person who cleans my house, despite me making 10x what she makes. There doesn't appear to be some global correlation between working hard or long hours and pay.