I see what you're saying and I agree that they're more of a "lifestyle business" as defined in this thread. They're not the traditional type of startup, but they do share startup values to an extent.
What I'm getting at is that 37 Signals, while they might complain about competition, probably isn't all that concerned because they have a healthy revenue stream. Their revenue may be taken away later, but they'll be able to deal with that the same way they dealt with no revenue when they were just starting: making something people want and straight-up selling it to customers. In the meantime they're making bank.
