> I also mathematically can't get behind the concept of reproducing a known state taking longer than the time it's taken to get to it.

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.