Damn 6 figs for knowing an old language? I wonder if there are remote jobs for that. I'm sure there must be resources out there to learn it.
It's just simple supply and demand on things.
There is a small supply of jobs left for old legacy languages - yet there are plenty of things like banking systems that are still (and likely for the inevitable future) will be based on those systems.
Thus, given the limited supply of jobs - it isn't a skill that is often taught or emphasized in school. I'll be honest, I took COBOL as a BUSINESS class (NOT a CS grad here) before I graduated.
But also since it isn't a skill that is actively taught, that limited the number of people that are qualified for the number of jobs still in existence.... And as old people that know COBOL start to retire.... that means they have to be replaced..... Limited supply = higher pay to meet the demand.
I'll also relate it to my work in tax. I can name 10+ people that I personally know that are CPAs....They also don't know jack fucking shit about taxation. People often associate those 2 topics - but they really don't necessarily correlate.
I guess my point is that I know plenty of general accountants that are paid $60-80k to do accounting work.... But doing work in taxation is a niche within the business sector that people often don't specialize in. Thus the pay is substantially higher.