The problem with migrating off COBOL is not COBOL. It is the fact that the business processes are not documented, and that they have been allowed to accrete special cases for decades. A very little of that results in unmaintainability very quickly, in any language. If the only way to deduce your processes is by reverse-engineering source code, in any language, you're fccked.
This was one of the few things I was hoping for AI to help with. Cobol is so clunky, and no one wants to work with it and to my Surprise, Cobol jobs don't pay as much as people think.
It's not our problem to fix, but I'm surprised the alarm bell isn't ringing at some of these financial institutes. Eventually there won't be people to teach the next round of employees that inherit these tools.