>That time spent thinking of how to plan a change goes away when you have a monorepository
Not entirely. Since the fleet isn't atomically updated to the next version you have to be careful about multiple versions being compatible with each other.
Upgrading software and Postgres databases is a difficult problem in general.
The text itself can be changed but it takes at least 15 minutes to mutate to a deployment. We still cannot generically mutate running code to other running code. Ksplice and other live kernel patching and Chrome's binary patching should be generalised and productised.
Patching methods at runtime is another thing that is possible (ruby, python and Erlang) but I am not aware of a general framework for deploying mutations to servers at runtime.
Not entirely. Since the fleet isn't atomically updated to the next version you have to be careful about multiple versions being compatible with each other.