This pretty much happened at one of my jobs. Principal engineer was airdropped into team and decided everybody would develop all new microservices with his new pet framework (literally, it was named after his dog) with Spring style DI cruft that was in many ways more difficult to work with than Spring. He enjoyed rulership of the team for a while before leaving for greener pa$ture$, and on his last day of work, he changed the README on the open source repository of the framework to point to his own, personal, repo as the locus for all future development. A move widely frowned on, especially by management and legal, which soured his reputation, and higher-up architects had different ideas anyway, so the pet framework was deprecated for future development.

Lesson: If you're going to code your way into being the only developer who understands the core abstraction behind your employer's critical code, do not overplay your hand.