Few places I've worked ever put improving the system in the plan. It's almost always said that "we'll work on it later, when we have time". Later almost never comes, of course. On the rare cases when there is a little time, the team will start something but have to abandon it when inevitably the business needs change and they get drawn to other work. Remnants of incomplete attempts speckle the codebase like bird droppings on a car parked under a tree for 6 months.