Cobol is often insulted for being "legacy" code that should be replaced with "modern" applications. The thinking is that these banks are using 40 year old codebases running on ancient IBM mainframes that have so many embedded assumptions and dependencies, most of which the people who created them are dead or retired, are becoming increasingly costly to maintain.
But what was once modern will one day become legacy, and I fear the hundreds of languages, technologies and frameworks will make this problem much worse! Cobol at the end of the day is quite simple. But what about legacy code using haskell, clojure, Java tomcat and several frontend frameworks, back end frameworks and distributed microservices, of course written in several languages each. In forty years, what hope will we have of understanding these things? Google has more than one billion lines of code, and it's only a few decades old.
Does anyone else share the same worry?