> Most people are very lazy. They don't want to take the time to think through new ideas or look at them in a new light. Once they've made up their minds about something, they don't change them. That's generally why most people don't come up with ideas for new or great things.

See "Theory X": http://en.wikipedia.org/wiki/Theory_X_and_Theory_Y

> I think part of the reason that people ask this question as a way of putting founders down is that they assume that startups are zero sum.

This sentiment has just gotten so trite. The idea that economics is not a zero-sum game is one of the first principles of capitalism.