Writing good documentation is super hard. I try to do it for my parser (https://github.com/norswap/autumn4/ https://github.com/norswap/autumn4/) which is < 10k

Writing good documentation is super hard. I try to do it for my parser (https://github.com/norswap/autumn4/ https://github.com/norswap/autumn4/) which is < 10k lines of code — both complete and useful Javadoc and a user guide. It's a lot of work, which would easily rival the programming if I hadn't had to tackle open/hard problems. Can't imagine how it must be for bigger projects. Another issue is that documentation is not a task easily left for "sub-alterns". It requires a good deal of understanding, finesse, and pedagogy. And it actually plays nice in a feedback cycle with the programming. The documentation is where you realize your tools is nowhere near as simple and friendly as you could (easily) make it. So the bottom line is that this requires massive investment which isn't always done this day. And personal accountability of individual developer/small team on writing docs and being into the feedback loop.