I'm from Munich and followed that very closely when it happened.

The reality isn't lock-in. The reality is lobbyism. Ballmer literally interrupted his skiing holidays in the 2000s to offer the then mayor a better deal when that mayor started the Linux project. But Ude stood firm.

Then the next mayor came, and with him, a new opportunity. Microsoft was planning to build near Munich you see, and it would be a shame if that had to be cancelled. So they met the next mayor, Reiter, behind closed doors to talk about the building project, and a bit after that, the (by then already clearly successful) Limux project was undone.

Not cancelled, that would imply that they weren't done switching everything yet. They were. They just did the whole migration in reverse because Microsoft wanted them to.