It’s been a while since I was told this, so not sure how true it still is, but there a was a niche but lucrative market for people who could maintain stuff in Fortran, COBOL and the like.

Because there were some critical antediluvian pieces of software in banking, big businesses, etc that some companies were terrified of having to replace one day.

I’d expect that by now most would have migrated to more common languages, but I don’t really know.