The market can stay irrational longer than you can stay solvent
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!
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.