my understanding is that companies with COBOL are big instituions with people not much interested in "career" but in "stability". So those old programmers stay

my understanding is that companies with COBOL are big instituions with people not much interested in "career" but in "stability". So those old programmers stay there until they retire (nothing wrong with that). So they keep up the COBOL system. Once they get older management thinks about replacing the COBOL system with something new. If it's really expensive, a new system is built around the COBOL system with new technologies : report by report, DB by DB, etc. until then old system can be unplugged. It takes 10 to 20 years to do so. Nothing unbearable for a big corp.