This doesn't square for me at all, or for many of the people I know. Granted, I don't live in SV, but I and most of the people I know in tech have a pretty relaxed working environment 90% of the time, far more than comparable positions in consulting or finance. I probably have about three or four weeks per year that are serious crunch time where I will work more than 40 hours, but for the most part it's loosely 9-to-5 and very amenable to work-life balance.