Open-Source in its actuality is not a lot about community. It's about making sure other people have everything they need to be able to run and modify a specific piece of software. The fact that, usually communities form around this paradigm is a happy coincidence in my opinion. Additionally, another point on both you and OP are missing the point, is that the communities that are relevant to open-source are not communities of users, but communities of contributors.

And what OP is proposing is actually forced labour. Instead of people being free to work (and fork) to their heart contents, the implication exists that they're losing their time, and instead, should focus on "collaborating" with the existing community. Which frankly nobody in the history of open-source ever denied. Forks are last instance measures, where the steering of a project gets off the rails to a high enough degree to justify such a drastic measure.