> Except it wasn't: Amazon--like everyone else filing a patent--had a duty to bring the idea to market within the time frame that US patent law required, which they then did. _That_ is the how.

That's not proof of non-obviousness. And even if it were, it's still not a reason to allow 'what' patents (which the law actually doesn't allow! But they get granted anyway).

> Demanding the patent goes into the specific details

You are arguing a strawman. A patent must describe the invention in sufficient detail for someone skilled in its art to reproduce. Incidental details shouldn't be (and I believe aren't, legally. What the USPTO actually does in practice is a different matter) grounds for calling an alternate implementation non-infringing.

What you're describing is a hideous perversion of the patent system. It allows patenting any obvious [1] idea so long as you are first to file [2]. Alternately, if the idea is novel and non-obvious, it grants patent protection without requiring disclosure of implementation. It basically grants patent protection to trade secrets.

[1] A test for non-obviousness: does an implementor care to look at your patent or reverse-engineer your implementation, or is a description of what the invention does sufficient?

[2] And eventually implement.

There's no requirement that you actually implement a patent to keep it. The patent troll industry runs to a large extent on patents that aren't being practiced.

You may be thinking of trademarks, which can be granted on the basis of an intent to use the mark in the market with a time limit thereafter to keep them.

"had a duty to bring the idea to market within the time frame that US patent law required, which they then did"

Do you have a reference for that ? I've never heard of any such "duty". There are many patents that have never been implemented yet remain valid.

Beyond that my point is not that they didn't show the "how" but that the "how" in that case was absolutely trivial and completely undeserving of patent protection.