I ran an ecommerce company for about a year, and one click checkout was the least of our concerns when it came to Amazon. The speed of delivery, prime benefits, brand recognition, and willingness to lose money on many if not most items are absolutely brutal to compete against. I'm glad one click checkout will be more broadly available, but it's probably not going to make much of a difference...
What I'm hopeful of is that (barring evil patents or monopolies) all of those things should be able to be outsourced a third party vendor or service. Hopefully in the future you will be able to simply contract out alternative delivery service, or drone delivery, or "prime"-like membership programs with the click of a button or an API call.