[dragonwriter]

The private repositories are limited to three collaborators. I think most people who would pay for private repos rather than simply use them as a factor in selecting among free hosts are going to need more collaborators than that before long (if not immediately).

Meanwhile, if people that just don't want to share their solo tinkerings focus on Gitlab or Bitbucket free plans for the private repos, then when they are ready to move up, GitHub is in a worse position to try to monetize them than if they were already in the GH ecosystem.