I’m sorry but this is simply not true. This has been discussed a lot before. I believe that Implementation variants: rehashing and refocusing provides the most recent summary.
Sure, we could have rebooted the discussion once again. However, I don’t believe that restarting it without any new data was likely to bring a different outcome. And at least I don’t consider myself capable of figuring out a solution to such a complex problem and figuring out all the potential issues in a purely theoretical way. Even if that were possible, I don’t believe it would be the most efficient way.
I understand your sentiment, and in fact I share it often. Say, when people give me complex patches without any prior discussion, and I am torn between accepting a patch I disagree with or discarding all the work the user already put into it. However, in this case I do believe prototyping was the appropriate cause of action, and all of us have done with the awareness that the proposal may require significant changes, or even be entirely unsuccessful. And as Jonathan already pointed out, while working on the prototype we’ve hit many issues that we did not anticipate, nor found mentioned in the previous discussions.
Yes, discussing on top of an existing prototype changes the flow of discussion. But more importantly, it means that we have much better understanding of the problem scope, which means that in some cases we will be able to answer concerns and ideas with actual experience and results, rather than theorizing. It also means that the discussion can be more focused, which in turn increases the chances of reaching a consensus rather than diverging in multiple incompatible directions, and of it being open to more people who simply can’t dedicate that much time to read all the possible angles that could come in a more generic discussion.