If you include thinking about work, then even work-from-home people could reach the 50+ figure relatively easily since you include weekends and trying to get to sleep. But then you might easily get into low numbers of hours per week, 15-30, if you subtract things like spending some large % of your time doing non-productive non-work (happy hours, lunches not at your desk, watercooler talk, browsing HN) even though you're at work.

Work time should generally only be the time between clock-in and clock-out. For professionals that are freed from clock-in-clock-out, I think they would still clump around that 40 hour figure if you made them clock-in-clock-out for the data rather than for the pay.

I manage a software team at a Fortune 20 company, and my developers have a ton of freedom. They can work from home any day they please, and I'm honestly surprised when I tell them, "You don't have any meetings for the rest of the day, go home." By no means am I an exceptional manager, but that statement is taken as suspect by most of my staff. Good software can't be coerced.

They also own houses instead of renting flats in SF with roommates.

I work 9-5 M-F, live 5 minutes away, and love my job. Keep looking, they are out there.

Sure, if you include all that I've been working 50+ hours a week for virtually my entire career. I don't generally count all that other stuff as "working", though, because I have some control over how much or little of that I have to deal with.

Are you seriously considering waking up and putting on pants to be working?