to be fair, that cobol program has been working for probably 30 years (maybe even longer than that) - thats unusually reliable and long-lived for a software project.
the only real contender in this regard is the win32 api, and actually that did get used in enterprise for a long time too before the major shift to cloud and linux in the mid 2010s.
ultimately the proof is in the real-world use, even if its ugly to look at... id say, even as someone who is a big fan of linux, if i were given a 30 year old obscure software stack that did nothing but work, i would be very hesitant to touch it too!
It still needs continual software maintenance though. The developers still making their money in COBOL make it because it doesn't just keep working untouched. (Just about no software does.)
I would like to add the business core functions of SAP R/3 (1992). Much of the code created for it in the early 90s still lives in the current SAP S/4HANA software.
