[p_l]

The big issue is that for considerable portion of extant COBOL software, you have to deal with entrenched runtime environment. Purely batch processing COBOL might be easier to move to newer languages... And possibly was already picked for rewrite.

Where you're going to hit major issue is with COBOL running under the likes of CICS or IMS, where sure, you can use some more recent languages, but what you'll get in the end will be possibly even worse because now you'll have to find Java programmer who knows CICS.

And CICS or IMS aren't that easy to replace.