While Apple has a lot more credit cards on file for registered users than Amazon does, the company lacks everything else on this list. One of the biggest hurdles facing any competitor to the online king is getting people to register and turn over their credit card info. Even big physical retailers don't have that information and customers tend to be reticent to give it even if they trust the store when they can just buy the item on Amazon.
Call it the advantage of malaise, but who wants to complete a registration when a perfectly viable site which already has your info sells pretty much everything at a fair, and often better, price?