Are you suggesting that investors keep startups from getting ludicrous office space? From my experience with well-funded dotcom startups, they all tend to spend staggering amounts on sexy office space. We're lightly funded, so we sure as hell didn't.
In any case, Joel isn't spending a shit ton-- he's spending ~4-6% of revenue, as he said. Decent investors would only involve themselves if you were spending an unreasonable amount of money. Joel could be up to his armpits in Series D financing and not have an investor blink at this expenditure.
(if it isn't obvious, I think it's a dumb expenditure for an unprofitable startup, and a fine expenditure for Joel)
(Although I'm unlikely to "let go" of the outside investor thing; I help run a bootstrapped company, and had a bad VC experience).
Or I was idly thinking once of a plan where you sprint for 3 weeks (still with weekends off) and then everyone has an entire week off.
Over and over, ~13 weeks of vacation a year.
I wonder if a refreshed, happy, and likely less compensated team like that could keep up with a full time one.
Between ludicrous offices and the 37s "4 days a week" plan, I'd probably go with 37s.