Buffet's company has achieved returns of 8% over the last 10 years. Amazon: 36% over the same period.  That's some solid track record, cute quotes from Charlie Munger notwithstanding. 
   If Amazon were to be just a retailer like Costco, it would not be commanding a PE of 160. The AWS has grown to 12bn/year from basically nothing three years ago, at growth rate of 70%. The retail side brings in 70bn/year. Margins in the AWS are well above the razor thin margins of the retail side of the house. In cloud computing, AWS is steamrolling over its competition, both on features and on price. And so people are betting on cloud computing to become widespread and on AWS becoming as important as retail in Amazon's future. 
  Also, people are betting on Bezos remaining the driving force and potentially opening up their logistics network and annihilating the likes of FedEx. 
  Maybe they won't be able to pull it off. But you can always invest with Charlie at 8%.