I personally refer to this as the "Marissa Mayer problem." To me the real mark of success and brilliance is not just succeeding once, its succeeding multiple times. Jumping on the Google or Amazon rocketship and doing well there, while there is something to be said about the fact that you didn't screw it up, doesn't necessarily mean that you are brilliant. She went to Yahoo, and while she did a decent job putting lipstick on a pig, I think it showed that she is a mere mortal and not a genius.

What is impressive about Amazon IMHO is that they have succeeded in multiple businesses. One could argue that they are all under the halo of "ecommerce" but what was just a bookseller spread into virtually everything sold online, reshaping distribution networks, moving into groceries, content, etc.