This 100%. From the tweets it sounds like the problem they were trying to solve was to make the app more modular so it would scale better to more devs. There

This 100%. From the tweets it sounds like the problem they were trying to solve was to make the app more modular so it would scale better to more devs. There were/are well established patterns for doing so in ObjectiveC. The Swift rewrite was not necessary and probably took a very difficult project and turned it into the death march that the OP describes. They should have solved the architectural problem incrementally without adding a 1.0 language rewrite to the mix and then slowly rebuilt the app using Swift. This is so obvious to anyone with experience it seems pretty evident that the decision making process there at the time was deeply flawed.