Indeed. If there is a market for COBOL programmers (and it's clear there is), then the obvious solution is for unis and colleges to spit out more COBOL-literate CS graduates. Honestly, if I was ten years younger, I'd probably delve into it myself. It is, after all, just a programming language, and hardly on the same level of trying to learn Sanskrit.
As long as you have a real fall-back so your career doesn't dead end. What can easily happen is that you do X then more of X because it's the only place you get a salary/career development until you've done X so long nobody will really hire you for anything else. I see this with for example some SAP consultants, essentially SAP customers want to hire you for your SAP experience and the rest of the world doesn't care that you have a general IT degree 5 or 10 years ago because your experience is all SAP-specific and they don't run SAP.
Now they're probably safe since that ERP is burrowed so deep into many companies they'll never get out, but for something like COBOL you could end up doing it for some years and then the legacy system is shut down and nobody wants to give you anything but a junior non-COBOL position. That is if they'll even hire you or if they'd rather have a recent college graduate. Or you might have to relocate to find one of those increasingly rare positions that actually value your COBOL experience, which of course only makes it harder at the next crossroads.
If you write cell phone apps as a hobby and can show them a portfolio or something, maybe you'll get away with it. No, you're not a dinosaur who only knows an outdated language and best practices from 50 years ago. Or some other way to be able to transition away from that COBOL career more smoothly. Some of my older colleagues noted that the parking inspector at work used to be COBOL programmer some 20 years ago, they updated their skillset and apparently he didn't.