My co-workers (SWE) used to work at Amazon and their wages were fairly competitive (ie, market rate). I'm not too sure about non-technical, warehouse jobs, but I would expect those jobs to be much lower. How much do you think they should get paid?
Maybe something that tracks how much value they produce for the company, or how successful the company is overall? The article says Bezos cut healthcare and pension plans, while the company is making more money than ever.
If he did that, then the company couldn't have gotten this popular. In the beginning, it was VERY difficult to get a better deal on products than Amazon because of how low their prices were.
If they started to pay their employees more, then they could have never priced their goods as competitively.
"But wait, that was then, why not start paying their employees better now?"
Because this is just the beginning. Amazon will use that money to grow even bigger by investing into itself. You don't even know what they might expand into in the next ten years. And yes, they will have to do it by paying their employees as little as they can get away with to keep growing the business at the same quick rate.