If you are wondering how Amazon can attract any talent at all, the answer is that 70% staff is college hires that were promised significant stock. The caveat is that it doesn't even start getting vested until after 3rd year. Most of the hires leaves in about 2 year (attrition rate is being rumored as much as 70%). So their secret is feeding the growth engine on huge swaths of college hires that can be lured for stock options in distant futures with expectation that they will just leave before vesting starts.
Well, I do love Amazon. One thing they have got absolutely right is obsessing about customers. Everything starts with customers, period.