The problem is not so much access to tooling, but access to mainframes. I can learn COBOL in a day or two, and I would love to work on a "boring" COBOL job, but I have no experience with mainframes.
Indeed, mainframes are hard to get access to, and require a training by themselves, I have worked on Linux and Windows for years, and development on a Mainframe has nothing in common :-)
I think the problem of COBOL is not only the lack of COBOL developers, it is the lack of expertise in COBOL environments, because they have become obsolete (both on mainframe and proprietary tooling for Linux/Windows). By providing a modern environment on Linux for COBOL, our goal is to solve the hardest part of the problem, as learning COBOL itself is not so hard for existing open-source developers...
But what I remember most: the two other students were mainframe programmers, and they were just as baffled by my world as I was by theirs. It really was an entirely different computing paradigm, although 30 years later I probably have enough experience to make more connections than I could then.