For me the reason because those initiatives all failed is because all of them started by some individuals and they where developed out of the tryton repositories so never became an “oficial documentation”.
If you plan to work on this in the long way I think we should first discuss how to develop a documentation, which topics we should include on it and then do a collaborative effor. This is the only way to include the documentation as part of the oficial documentation and do not have a new failed attempt. It will be good to start a new thread for this discussion.
Another point that we failed to get documentation is that we have the fear to have an uncomplete or outdated documentation. For my point of view, both documentations are better than no documentation. I think we should low the starting point of the documentation and write them step by step. Once we have some patterns and some starting point we can use a crowdfunding campaing to make someone work on it.
I will prefer to do not have any hurry on this topic but do little steps to complete a long way. But what is clear is that someone have to take the initiative.