The hard part of OSS management is dealing with change requests. Something comes in and now it's on the maintainer to ensure that the new fix doesn't break anything existing, or the new feature doesn't collide with anything else that comes down the pipe later. It's not work that can be done by volunteers, it's something that can only be done by long-term maintainers.

When I worked on an OSS project I hated getting PRs. They usually wouldn't work for one reason or another and I would have to explain why they were problematic. It took a lot of time out of my day—I would rather people just submit bug reports and feature requests.