Amazon does not pay taxes on profit, because Amazon makes so little profit.
Amazon makes so little profit because they spend it all on expansion.
The tax system encourages expansion.

Someday when AMZN changes from a growth stock to a dividend stock, AMZN will start paying taxes.

There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. -Ernest Hemingway
The man who makes no mistakes does not usually make anything.-- Edward John Phelps