I'm not the poster, but I have a story which might elucidate this.
The application I was working on, which had a C++ front end for a mainframe with three databases involved caused an IMS segment to crash. The guy who saw the message got in touch with our senior user and discovered exactly who was doing something to cause the IMS segment to crash. This was at about 4:30 on a Friday in a corporate government type office where about 4 out of 5 people had already gone home.
Within 30 minutes he had examined the crash dump, pulled out the COBOL program that had caused the issue and found the constant that had been set 20 years ago that had now been validated. He quickly go the user to alter the case so it didn't happen and he and I put in place new higher constants to protect the data from being damaged in future.
It was damn impressive.
But well, there are guys like Raymond Chen at MS who can do this for windows programs and in about 20 years, when node.js often means terrible hacked together code there will be JS gurus who can do the same.
But if the mainframe systems are still in operation, we have to hope those COBOL guys are still around.
What would be this "breed" of person you saying? Could you elaborate on this? I'm genuinely curious