All of the software that runs on the numerous parts of my websites is Open Source these days. I am clueless at programming so I am not in a position to contribute to development of any of the software I use, but I do try to help by being part of the support lists of several software packages I use and regularly answer newbie questions that constantly keep popping up and that I can answer based on my own experiences.
Along with requests for help, of course, people submit feature requests and inevitably with silly regularity someone shows up to ask that the developers stop what they’re doing on the core of the software to bake a commenting/discussion system into the software.
It doesn’t matter that the developers are usually working on the software in their spare time and barely have time to work on the core functionality. Nor does it matter that there are several hosted commenting systems that can easily be used for this purpose (such as Disqus) or that there are literally dozens of open source commenting and discussion systems available that could be easily used for this purpose.
But no, that would never work. So instead people show up and ask — and frequently demand — that the developers reinvent the wheel just for them.