Yeah, I think there's definitely a lot of survivorship bias involved. COBOL was IBM's biggest suggestion at the height of IBM selling every business that they needed a mainframe to run their core business. For a brief era "every company ran on COBOL [on IBM mainframes]" and those programs were core to a lot of those companies' success stories. As computers moved on, the programs that survived in COBOL were already critical to business success. Every decade fewer COBOL programs survive, leaving only the "critical" ones left. Tautologically that survivorship sometime implies that COBOL itself was a key ingredient that made them critical programs, but mostly they are just critical programs because they survived that test of time.