I've prepared analysis for a projects for a steel mill. And I've dug into other people's analysis to find out how they come up with the numbers.
You can quote the top of the line equipment.
Estimate all machinery only works up to 75 percent of estimated life.
Estimate the costs of replacements will skyrocket.
Estimate that the manufacturer will stop supporting the equipment after 10 years, therefore require complete replacement.
Estimate the costs of maintenance workers will go up A LOT.
Insurance for the above workers.
Then, the side that you wish to happen, well..
those workers wages will barely go up.
Parts will last forever.
Parts will be plentiful.
etc.
This. I sometimes sit in meetings discussing a proposed solution, ask some tough questions, get some half-assed answers, and it becomes evident that the “solution” is a pet and it’s happening whether it makes sense or not. It’s often a solution to a different problem than the one we’re trying to solve. Like say the problem we’re trying to solve is searches run too slow. Well, if we use this square widget we bought and throw enough code at it, it could fit into a round hole. So then it becomes apparent that the real problem they’re trying to solve is that that they bought something expensive and they need to justify its existence.