I honestly think that it could be a good business model if you could get the marketing and "distribution" right. Lots of people order their games online anyway, so what it you cut out the publisher and went straight to these sites with some kind of distribution deal. Particularly if they're not holding warehouses full of games, it must pay them to help you sell the game. With the higher royalties for both parties it will make games easier to hit the break-even level for the developer and the distributor has more of an interest in its success.
The trick is getting the game into development in the first place, though.