I like the Sharks not Dinosaurs thing. i keep see people saying "the FAA system was so old"... being old wasn't the problem, lack of maintenance is the problem. We have roads that are old, bridges that are old, buildings that are old, planes that are old, ships that are old, that still do extremely well.
Rewriting COBOL in Javascript is not going to make a system more reliable. Making a system reliable is what makes it more reliable.
Rewriting COBOL in javascript would make the codebase accessible to a larger pool of potential engineers who are also more likely to be up-to-date on best practices (as opposed to an engineer that has stagnated in COBOL for 30 years.)
I'm not sure a rewrite is warranted, but a system isn't maintainable if there aren't enough people trained in the particular language / tech stack.
I think conditional probability of a Javascript programmer knowing best engineering practices is so much lower than that of a COBOL programmer, due to large numbers of unqualified Javascript programmers, and much higher average experience of COBOL programmers.
oh please no JavaScript- it is awful enough in the frontend, but that train seems to have left the station, but in the backend we have much more powerful languages and ecosystems.
Rewriting COBOL in Javascript is not going to make a system more reliable. Making a system reliable is what makes it more reliable.