You're assuming that I have any ownership of J, which I don't - it was written to work in a particular pattern that the CIO favoured five years ago, before he left to work for a consulting firm.
Also, A is a 30-year old legacy system sitting on a mainframe, B is an Oracle database inherited when we bought over another company, and Z is a third-party who we're shipping data to for their just-in-time procurement system.
"You're assuming that I have any ownership of J, which I don't"
No, I'm not. I'm simply taking seriously the claim that the arrows are more expensive than the components. If that's true, then it's cheaper to rewrite J, period, by definition of the claim at hand.
If it's not cheaper to rewrite J, then the arrows are cheaper than the core components and the way in which they are more expensive is only in an artificial and useless measurement of "cost" that only holds up as long as you don't take it seriously... what's the use of it, then?
The problem there is that there are already several arrows pointing to J. So if I change J then I have to update all of them too. And then have them regression tested.
(It's usually the cost of regression testing that causes the most crustiness.)
Also, A is a 30-year old legacy system sitting on a mainframe, B is an Oracle database inherited when we bought over another company, and Z is a third-party who we're shipping data to for their just-in-time procurement system.