In 8 years I saw it once. A mobile app lead dev couldn't increase his salary at his old company, and they seemed a bit stuck on allowing him to do certain thing

In 8 years I saw it once. A mobile app lead dev couldn't increase his salary at his old company, and they seemed a bit stuck on allowing him to do certain things. He joined my workplace at the time and was responsible for an app that moved nowhere. After 8 months he'd refactored the entire app, couldn't come up with more to do, and was slightly frustrated about the pace and anarchy, and he negotiated a deal with his old employer, who had realised how valuable he was. Nobody was upset, it was all cool. I often considered joining an old employer. I never did because the ways in which they were stuck are still true, and I think "changing the system from within" can be a lost cause. But if I were truly stuck, I'd know who to call.