I disagree that margins are everything. Volume and efficient fulfillment are more important. Look at Wal-Mart's margins. Amazon doesn't have Wal-Mart's asset turnover, though. Nor are they likely to, if they get too heavily into the mix of warehoused goods that Wal-Mart covers so well.
Cash flow is the focus.
Nobody expects Amazon to be a high-margin company. Look at the latest balance sheet and cash flow statement. Float diminished and cash flow worsened as payables went way down. That's a loss of leverage, possibly because of the recent unpleasantness. Looking at the past quarter, one of the weakest of the year, is not a good way to judge where the company may be five years from now.