I happened to be in New York a little over a year ago. Going down to check out Occupy Wall Street, I took a wrong turn and wandered into a high-level organizational meeting.
They struck me as very similar to a startup in culture. Smart people with mutual respect and a shared mission dealing adaptively with complicated issues. Rapid delegation, low on hierarchy, experimental, collaborative, supportive. I was impressed as hell. It was very different than the culture in an established hierarchical organization.
I agree that startups are up to something fundamentally different, but that doesn't mean that they don't have a ton in common.