If Amazon succeeds with this now then this will be a really good example to disprove the concept of the first mover (or maybe in this case hundredth mover) advantage forever.
Can't say I ever really agreed with the first mover advantage. Looking back, it's usually someone who comes later who really "gets it right", now that they have the perspective that the first guy laid out for them. As a first mover, you've got to be constantly changing to keep up with these newcomers.
If you can't be first, be best. If you can't be best, be first.