Also, business people don't like things to think for themselves, so Lisp would be risky in that respect.
Just think about it, I can run my PI servers on COBOL without the intricate, ever-failing dance of dependency from externally sourced, crufty packages, whose security holes eventually get opened wide by the latest DawnSpreader or Mousy Trick-Track exploits. /s
Wait... maybe there is something there after all...
It gets even worse: I got stuck for a year once working on COBOL software that only ran on Solaris, depended on Micro Focus's buggy and slow $3000 compiler, did binary searches across flat files and depended on Unix calls like mmap(). I got it up and running long enough to see how the code worked so that it could be rewritten in Pascal (this was chosen because that's what the guy I was working with preferred).
COBOL is a terrible, verbose language that doesn't even have local variables. It belongs on the ash-heap of computing history, not in any project that should be maintained today.
There are commercial software packages for re-hosting mainframe applications to other platforms. These typically provide not only COBOL and PL/I compilers but also functional equivalents of CICS, VSAM, JCL (JES2), and other mainframe system software.
So an open-source/free version of one of those "re-hosting" packages sounds like it would be useful for someone wanting to learn about cobol + mainframe development, but I can't imagine that ever happening (demand can't be too high) lol.
A. ADD 1 TO COBOL
Oldie but a goldie.
Their variant of COBOL has a number of extensions beyond the regular standard in GnuCOBOL. One that springs to mind is around data serialisation and file formatting.
They also implemented an API layer for access from more modern stacks.
Incidentally, if you're interested in getting into software development, I believe the DWP in the UK are still currently taking on apprentices to work on the COBOL-based systems in the department - I think they also get training in other languages too - perhaps JS, Ruby or Python?
It's extremely rare to see FOSS in such legacy systems. The push for FOSS in large corporations has been coming from the for newer stacks, designed by newer developers.
Cobol itself is pretty evil to learn and not comparable to most c-like languages. I think the fact that it was so intimidating set me back about 10y on learning programming as I always just assumed it was too hard.
Source: I have experience with COBOL banking systems. Horrible, horrible programming language.
To your point about not making 'big bucks', you're right, but it's nothing to shake a stick at if you really want to get after it.
Those of us who actually worked with COBOL know it's an awkward language used for legacy systems, and which should be avoided -- and definitely not learned now -- if you can get any other programming job.
No, COBOL is not "fun". No, it's not a good programming language. No, it's not the best money making opportunity. No, COBOL programmers aren't making lots of money. And the downside of getting a COBOL job is pretty big: you have to use COBOL.
This week we already had three COBOL related posts to HN (that I saw), one of them of the "you should learn COBOL" shill type.
The community of COBOL researchers is growing exponentially!  It's best to start with COBOL development in order to be an expert when COBOL's use really explodes.
But let me ask. Would anyone hire me having 6 years COBOL experience from late 90's to early 2000's?
Can you create a HTTP API with COBOL as well ?
Well, at least you could in theory with CGI, couldn't you?
This seems like a suitably unlikely pairing to be "interesting".
The first artificial neural network was invented in 1958 by psychologist Frank Rosenblatt. Called Perceptron, it was intended to model how the human brain processed visual data and learned to recognize objects. Other researchers have since used similar ANNs to study human cognition. 
COBOL is a high-level programming language first developed by the CODASYL Committee (Conference on Data Systems Languages) in 1960. 
A COBOL-like neural network simulation language based on layer macro definition 
Perceptron in COBOL 
My first program in COBOL, a single neuron neural network. 
Very good, I almost can call it Turbo COBOL on fast machines.