I mean, they do to the extent that they can. We have a story template that specifically mentions performance, monitoring, security and documentation requirement

I mean, they do to the extent that they can. We have a story template that specifically mentions performance, monitoring, security and documentation requirements. We also have weekly meetings to discuss technical issues and a dedicated backlog where devs are supposed to put purely technical stories, but it is usually empty. When the prevaling philosophy of the dev team (or its most vocal members) is "'good enough' is good enough", then there's not much the project management can do short of forcing a minimum amount of maintenance tasks. Of course, project management is also happy if they have more capacity for feature stories, so the impulse has to come from the dev team.