Edit: further, the problem with transpiling is that these systems are still under active development. For example, banking systems have to be updated annually f

Edit: further, the problem with transpiling is that these systems are still under active development. For example, banking systems have to be updated annually for changes in regulations and tax laws. If you translated all you COBOL to Java (which results in truly inscrutable code (cobol has unusual control flow constructs, even besides go to)). Then as an organization you're face with either modifying the Java code (this is very, very, very bad), or regenerating from COBOL periodically, which kind of defeats the purpose.