Zooming back out a bit: what are the demographics of successful startup founders? My intuition is that they're not a mirror image of the demographics of the country as a whole. There are a lot more well-off startup founders who went to CMU or Berkeley than there are startup founders from East St. Louis.
It's not a problem if a person picked at random from the population makes 50 million dollars with a photo sharing startup. But it starts looking a lot more like a problem when we're not picking people at random, but instead picking them mostly from the ranks of the most privileged people.
And still! I don't give a shit! I really don't think startups have much to teach us about income inequality and I don't generally believe they're a big Part Of The Problem. I'm much more troubled by the mere idea that startups might be a good lens through which to examine inequality and public policy.