I will say the obvious: documentation sucks because good writing is a highly skilled activity that takes a lot of energy for most people to do, AND because keeping it up to date takes a lot of time, no matter how good you are at it, AND because leaders of companies don't want to spend ANY money on tech writers.
That's it. No mystery.
(BTW, this would also be why company financial records would suck, if management decided to save money on accounting staff and have all employees just kinda do their own accounting for the company. I SAY HIRE A SCRIBE FOR EVERY TECHNICAL TEAM!)
This. Yes, having everything written down and searchable is definitely a good goal. However, in my experience, the people in most companies have very different skills and few are good writers. So it probably takes a lot of time to create an organization that has a good process for creating great documents, let alone to transform an existing organization which can do so.
Ironically, it is much easier for me to write good documentation if there are a couple of meetings scheduled around it. Having 3 joint sessions with at least another person is great, first to get the "bone structure" of the document, then to confirm that the "flesh sits right", and finally to resolve any unclarities that might be left.
That's it. No mystery.
(BTW, this would also be why company financial records would suck, if management decided to save money on accounting staff and have all employees just kinda do their own accounting for the company. I SAY HIRE A SCRIBE FOR EVERY TECHNICAL TEAM!)