I've done migrations off my. Savings were 8+ figures/year, so worth it, but, the application didn't have a lot of development. Several companies tried and failed; in addition to all the issues described, you find random bugs in the source coffee that just happen to work.
Cobol also has goto statementsv and unions, which lend themselves to really hard to follow code.
Cobol also has goto statementsv and unions, which lend themselves to really hard to follow code.