I can certainly understand your perspective given what your experience seems to be. However, the objections you’ve mentioned here don’t really hold up.
Yes, much of the world’s code base is in COBOL. However, I do not believe you can honestly say that each and every problem solved in COBOL necessitates a roll-your-own approach.
I don’t really have visibility on what precisely your own work involves, but I find it hard to believe that it uses no design patterns, no established norms, and no common concerns with the rest of the software engineering world. If that is the case, I’m comfortable calling your work an anomaly.