I'm sure you can still find COBOL work listed somewhere. That means it's useful to employers. Are such employers right to maintain such a base? I don't know. But given their decision, right or wrong, do they then find it more useful to hire Oracle guys, or COBOL? I would think they'd want to upgrade. And to the extent hierarchies are intrinsic to their dataset, Oracle does allow for recursive retrieval if an explicit 'path' approach is not used.
Upper management won't care about this:
"Oracle does allow for recursive retrieval if an explicit 'path' approach is not used."
It's always been that way.