I think they are betting that any of this code is transient and not worth too much effort because once Opus 5 is traimed, they can just ask it to refactor and fix everything and improve code quality enough so that things don't fall apart while adding more features, and when opus 5.5 comes out it will be able to clean up after opus 5. And so on. They don't expect these codebase to be long lived and worth the time investment.