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!