> I kind of suspect few people actually want 1-click checkout to begin with.

This.

I trust Amazon almost implicitly. I know that they have all my information, and that I use the same shipping and payment method every single time. There should be no reason for 1-click checkout to not work perfectly every time.

And even there, I don't use it. I dunno. Is it really that much more effort to look at one more screen and get the feeling of security that the item is going to the right place and will get there on a day that makes sense?

If Amazon can't get me to use 1-click, No other merchant/retailer has any hope whatsoever.

It works for digital items (iTunes, Kindle) because the delivery is "to me, in the UX i'm using right now", not a physical item that has to come to an address.