I understand what you're saying, but does this logic hold over decades?
I'm obviously not saying banks should just switch today cause it's easy and all, but if the ROI on switching is 10, even 20 years, it still makes sense to do if you're a bank.
I'm obviously not saying banks should just switch today cause it's easy and all, but if the ROI on switching is 10, even 20 years, it still makes sense to do if you're a bank.
I can't find the post now, but some folks from the US govt who frequent HN talked at length about the ongoing replacement of mainframe-type services with newer tech. What I gathered from that is that the cost isn't ridiculously low at all when you take into account the impact it has on the organization's ability to get things done.
What you have to remember is that when the COBOL code was written, it replaced hundreds, maybe thousands of people doing manual data entry and manipulation, maybe even pen-on-paper. That gives you a fantastic ROI. After that's been done, replacing one computer system with a newer one is completely different, a spectacular case of diminishing returns.
You are at a known state but you now have to re-create the steps to get to that known state as I'm sure a lot of the domain knowledge around the product is not there anymore. Not only that, you now most likely have other sources consuming the output of the original COBOL application so you have to ensure that the other applications are able to consume the new data and that those don't break either.
I've seen it attempted first-hand and it was a dismal failure. And it was their third or fourth attempt. And it wasn't even a full replacement! Just a simple data lake to dump things into. Google or Facebook or Amazon could do it, but few companies are like them.