Maybe we'll see a physical 'Amazon Store' where you go in, and they have one of each item available to see, no extra stock held, no risk of theft, etc. Minimal staff required, cutting down on that overhead. They could even have kindles on the walls to let you flick through books before you buy, listening stations for mucic you order to be delivered etc.
Would really cut the overheads of a high street, whilst allowing a large range of goods to be stocked, with the 'convience' of home delivery the next day too.
No instant gratification in you shopping to be sure, but I can see advantages.
P.S. anyone wanting to use this idea should apply to me, its mine now, etc.