If so, that explains several observations: the anecdote-based disagreements that keep coming up about the need for business folks, the general bias of YC for consumer web startups in the early years (I think they tended to fund all-programmer teams more so than they do now)
It also seems incredibly useful for figuring out what your startup should do, far more useful than whatever idea you have this week. The skills of the initial team are perhaps the most immutable of resource constraints you have. If you don't have a business/sales guy, don't get into selling software just because "37signals told you to." If you are a business guy, don't waste your time on a twitter app or social network.
Like Dijkstra said, "Do what only you can do."
And yes, I'm aware of Mark Zuckerberg, patio11 et al. Are they counter-examples or exceptions?