Would startups be better off if their founders only worked 40 hours a week? I don't think so - working crazy hours is a competitive advantage of startups.
Of course, motivation is the big difference, but that's a whole different argument than Joel is making.
How old is MS Office now?
Compare that with Silicon Valley startup mentality: code like crazy, take shortcuts, release early, flipped your company and let the new hires figured out the mess.
(Or you could opt for re-writes like the Reddit people have been doing since their inception).
Once you've expanded to the point where you have people who only program, Joel's advice is probably good: "encourage your staff to work a sane 40 hours per week" except for occasional bursts.
Joel is a pretty smart businessman and a lot of the articles are written within the management of an established software company frame of mind. Remember that:
- FogCreek is not a startup
- FogBugz has a long ship cycle
- products developed are mature
- code base is being used over a long time frame
- good software takes 10 years anyway ~ http://www.joelonsoftware.com/articles/fog0000000017.html
Quite the antithesis of what you might associate with Startups discussed here.
John.
That said, I can't imagine any startup getting far by working 40 hours a week. 80-100 is probably a minimum for a founder... it has to be your focus, not just your 'day job'.