Maybe I’m missing the point, but if you want to have union of maintainers/contributors, please go ahead, just be careful with assuming it can actually address the problem. You will never have any substantial percentage of maintainers. That’s kind of the main point of FLOSS: people do what they want to do, where they want to do.
If you want to collect data about what is used – with the goal of “not forgetting the little project with the library”, that’s also great but that’s going to be a lot of work and might be impossible to reflect. I can’t think about solution that would not be platform-specific.
Don’t get me wrong, uniting FLOSS developers along common goals, technology domains or philosophy, building communities and providing support systems is an absolute wonderful thing to do, even if you end up having what might feel like just a few projects.