Started my career doing Y2K stuff in 1998 and I still touch COBOL here and there today. I have a 10,000 line CICS program that runs every 30 seconds that I wrote in 2010. It has never failed since.
That's what I liked about developing Oracle stored procedures activated by cron jobs. Ran for 5 years, no maintenance needed.
I don't understand these "never failed" comments. Without further context, it's meaningless. If I write a python script and never change anything in its environtment or inputs, it won't fail either. That's not specific to cobol.