Many patents don't reward the first person who solves a given problem, so much as they reward the first person to encounter a given problem. That person adopts a trivial, obvious solution and the USPTO cheerfully rubber-stamps it at everyone else's expense. This was clearly one of those patents. It cost Amazon essentially nothing to research, nothing to develop, and nothing to implement, but the rewards were immense.
This is a good way of describing the point of patents, thanks :-)
This depends on whether you consider X to be "converting ecommerce sales" or "ordering items with a single click". Just because the implementation is easy to reverse engineer from a one line description of the novelty doesn't diminish the resources spent by Amazon in coming up with this insight and testing how it improved their business.
I'm not strongly in favour of software patents in general, but the argument that this patent is "too easy to copy" misses the point a bit.
The one-click patent has an implementation, but the implementation is so trivial that there are only two things you can do with it: either copy it wholesale, or write your own based on the same idea (which will have nothing in common with the original because they're both too small to "share DNA" like that.) In this case, you can't copy wholesale, because copyright. So you're stuck writing from scratch. At that point, the patent has given you no advantage in implementation over the simple knowledge that a process for doing X exists at all.