In my experience if the system is important enough, once you ship a couple of features to production you can coast there until the system is replaced. If the features were core the better.
I don´t like it but after 2 decades of coding I have come to accept it as it is.
I think a good way to frame the role of a SW developer is you are in a sense a manager of a new "team".
But instead of developing new hire training material and recruiting/managing people to do the new task, you're developing/training/creating/deploying software programs/scripts/bots to do what needs to get done for the organization.
While infinitely easier than dealing with HR problems that humans bring along, your team of programs/bots still needs some manager.
And just like a traditional manager, if you set up your "team of bots" just right and handle all the corner cases in the training manuals, a good managers job will actually ideally not be that hard day to day - particularly since the meatspace problems have been abstracted away.
I don´t like it but after 2 decades of coding I have come to accept it as it is.