I think Jeff answers his own question when he refers to my entire so-called "professional" programming career.
The fact is, there are a lot of professional programmers doing a lot of work that don't mix in the same circles as Jeff. The fact that they don't read his blog, or post to StackOverflow doesn't mean they aren't out there.
The sentence after that one says: "That probably says more about my isolation as a programmer than anything else".
The point is valid, if only to speak of an interesting separation and the generally low-visibility of COBOL in parts of the programming industry.
I can't say I've met anyone who is still actively writing or maintaining COBOL code either. I know a few people who wrote COBOL at the start of their careers, but who have since transitioned into other things.
So I think the validity of the observation stands. A quick straw poll of my colleagues within earshot (yes, I'm reading HN at work) suggests that none of them know any active COBOL programmers either. This is from a group of people from very junior to very senior, with a range of about 1 - 20 years of commercial programming experience.
Which observation? That the COBOL-type programmers (and we can add in RPG, and other non-sexy languages as well) are isolated from the rest of the industry? Sure. But in-house developers of serious, back-end-heavy apps have always been isolated-- including from each other.
I think if you started calling around to banks, hospitals, transport companies, oil companies, old-school manufacturing facilities, etc., and started inquiring about their existing codebases, you'd get a whole other set of anecdotes.
The fact is, there are a lot of professional programmers doing a lot of work that don't mix in the same circles as Jeff. The fact that they don't read his blog, or post to StackOverflow doesn't mean they aren't out there.