Actually the opposite is true.

Actually the opposite is true.

The problem is not: "Does it makes sense?" but "Can it be financed?"

The last bank that I worked for had 40,000 mainframe programs alone for the share trading to end-customers (don't know the correct English term, equity management?). Rewriting these programs with the same functionality is just not worth the investment.

Since few specifications are available, rewrite them for new functionality is difficult as well. These programs literally evolved over decades and added all the special cases that must be handled. New software first have to re-discover all these special cases and re-program them anew. And believe me, it's no easy thing to analyse a twenty-year old COBOL program that has been actively changed all this time.

Oh yes, this bank tried that and failed. In the end, they had to write off 500 million Euros for the cancelled project. (And that was hard cash, not stock money.) It is a lesson for all those who think they can rewrite two decades of software assets on a whim.

Concerning compute clusters: These are not relevant for this realm. Most of the time, these programs don't compute, not even addition or multiplication. They just move data from one place to another, or update data. Performance advantages in database technology is the key to get them faster, not parallelization of applications.

Cheers, Joachim