I find most answers I need on Stackexchange. However there are books like "Mac OS The Missing Manual", I always wondered if anyone bought them and what they actually contained.
My thoughts exactly. First thought was what problems did this person run into that can't be found in a single google hit today? I was thinking the piece would go into some obscure internals but that doesn't seem to be the case.
MacOS is simple enough to grasp for most people at first use. More advanced usage is documented, not in one location but scattered over the internet. Google made that not matter anymore.
In addition, most documentation you would need today is for the products you install I guess, not macOS. But again, it really doesn't matter much with Google finding anything you search.
My experience with (large) documentation projects. They are outdated almost always. Q&A style works much better nowadays.
I believe that's only true if the questioner is versed in "How to ask questions the smart way," and/or the answerer is _also_ versed in that, so they know how to answer what the questioner was _really_ asking
Not to mention the tons of "dear lazyweb, do my homework|task for me, kthxbai" level of effort expended by the questioner