The article DOES recommend using different languages for different tasks. A large part of it was about Ruby and Python shops that added Haskell to their toolbox

The article DOES recommend using different languages for different tasks. A large part of it was about Ruby and Python shops that added Haskell to their toolbox in order to clean up overly complex parts of their codebase. As far as the supply of programmers is concerned, if a software developer is TRULY talented, then they will be able to learn a new language in a couple of days, and learn a new paradigm (such as functional programming) in a couple of weeks. I say this as a person who has moved from imperative programming to object-oriented programming to functional programming over my career. And I have used so many languages that I have difficulty even enumerating all of them. They range from machine language, to various assembly languages to FORTRAN, COBOL, C, Visual BASIC, Java, Python, Ruby, Scala. The hard part of programming is not the coding. It is the DESIGNING. If you do the design part well, then the code flows from your fingers naturally, and you end up doing very little debugging, especially if you practice TDD which forces you to debug problems within 15 minutes of creating them.