This is not so much about 'hard work' or 'idleness' it's about 'identity', which errs towards a certain kind of professional identity when one is working all the time.

It's a very real phenom.

Also - consider that most 'extremely hardworking' bankers and lawyers are not creating jack (!) rather, they're competing with one another for customers and status. If they all chilled down none of us would notice in terms of lower value creation.