This. Right now, Amazon has about 40 billion dollars of cash and is generating another 10 billion a year and growing. Shareholders don't mind companies investing in future earnings but once they start having too much cash on hand signaling they don't know what to do with all of it, they will start clamoring for share buybacks and dividends just like what they are doing with Apple and Google who have had too much cash on hand.

I would make a large bet that Amazon will announce a share buyback and/or dividend in the next 5 years.