I agree with your first premise (that startups don't create new technology), but not the second premise (that large, established companies do).

Read 'The Sources of Innovation' by Eric von Hippel. It reaffirms what your first point, and shows that real technological progress usually comes from users of technology rather than producers (or, to put it in a better way, from cooperation between users and producers). More precisely, innovation happens when there is a feedback loop where users use technology in creative ways (according to needs not foreseen by the original producers) and producers incorporate those ideas back into their products. The contribution of the producer is to identify creative uses of their products and formulate business models around them. Amazon's cloud computing initiative is definitely consistent with this point of view.

Another major source of innovation is academic institutions, where risk-taking is encouraged when it comes to new ideas. Of course, it's also true that established companies also fund research.