It's not a cost - it is a money saver
I remember visiting a foreign bank a few months after a major outage. After the event the CTO brought in an enlightened manager (and some of his old colleagues).
Instead of being a cost - he sold the IT systems as saving money. "If you are not part of the solution - you are part of the problem" and several senior managers decided it was a good time to retire.
They got rid of paper and used pdfs They managed to shrink the pipeline so things could be approved in hours not days (or weeks). Managers now had time to manager, not shuffle paper ( nor signing things).
Due to take overs they had several bespoke systems doing almost the same thing. They picked the best one (eg for loans) , and migrated all the bespoke loan systems to one. There was a 6 month bulge in spending, but then they got rid of old systems, and saved money in licensing costs. Some systems they virtualised, and so got rid of old hardware and made better usage of the existing resources.
He charged back costs to the departments, so now each department had to pay it's cost rather than have IT centrally funded. The heads of departments had to go to the CTO and discuss the cost of running their department. After this meeting the heads of departments were more than happy to let go of bespoke, expensive systems, and use the "off the shelf" system provided by the enlightened manager. When they saw progress, the heads of departments were even more keen. I think he was promised 1% of the savings, and retired a few years later a rich man. Getting rid of idle old, hot machines saved them a lot of money in electrical power and aircon.