Yeah, I had an unexpected insight into all this as growing up, my best friend's dad was a COBOL programmer for Metlife insurance.

The upside of those old mainframe centric systems is they do have impressive reliability. But you increasingly become dependent on just a handful of old souls like my friend's dad that are the only people who understand it in sufficient detail to try to update it.

My friend's dad had good job security but it seemed pretty demoralizing otherwise.