> The question though is whether some other developer could, given the idea of "1 click buy", create this "invention".

I totally disagree with that. There's even apocryphal story that when 1-click purchase was implemented, developer actually couldn't resist of adding "are you sure" message box, because just click and buy is so against typical patterns.

I can give another example - socket wrench. Ratcheting wrench was patented on 1863. It took 110 years to invent quick change socket for it, although if you look at it you will say - well, everybody could create that invention.