a16z touches on this, but it has wider reaching implications than just Amazon's revenue.
I was a seller 5 years ago on Amazon and seller support was terrible. They use automated bots to ban your seller account and then offer no recourse or support beyond scripted emails.
I would think that if sellers like me were bringing in that much revenue for Amazon..that they would treat me a little better.
I guess this is the textbook example of why any sort of monopoly is bad.
Compare to eBay, where a fairly recent transaction by my father, buying an iPhone, was a scam, the cellular radio didn't work (rest including WiFi did), and the seller, who officially had a good reputation, knew exactly how to game the system so my father was out > $100.
It doesn't stop people from selling on Amazon though since it's almost a required channel these days.
Contrast this with the fact that an average Walmart does over $100 million a year in revenue (though Walmart's margins are closer to 1%), and it's actually not that huge.
So I thought I'd throw this comment in here in case others were misreading it as I did.
They had employees, but were still entirely owned and managed by a literal "mom and pop" whose children I went to school with.