Companies are greedy, taxes are ultimately paid by consumers - should a tax become higher for amazon or any other company, they will immediately raise the prices of their products to compensate the profit losses.
every other company that does pay taxes loses to amazon on this though.
One difference is that when taxes are fairly paid by companies and they raise prices, then the company that can offer the lower price due to operational efficiency will win. Right now, the burden of taxation falls on other persons in society without such tax avoidance expertise and muddies the waters.