The idea is that they let you stay locked in for free. They dissuade people from making their CI pipeline forge-agnostic by charging you if you if you take steps to not be dependent on them. This means they can keep charging in other areas, and keep people in GitHub so that it stays dominant. Dominance is something that can be used to keep people in the Microsoft ecosystem, keep GitHub as the place where code goes so they have training data for LLMs, and dominance can simply be cashed in down the line.

I don’t know if that’s actually why they’re doing this, but it sounds plausible.