Depending on the nature and scope of changes, forking offers a social advantage: pressure on the upstream project to merge your changes or risk marginalization.

Depending on the nature and scope of changes, forking offers a social advantage: pressure on the upstream project to merge your changes or risk marginalization. The described methodology largely avoids that pressure, yet the amount of effort to maintain a proper fork probably ends up being less work overall, as one can poach talent from the upstream contributor pool.