Currently it is the case that certain languages are better for specific problem domains, but that's mainly a library issue or a platform constraint (e.g. web ap

Currently it is the case that certain languages are better for specific problem domains, but that's mainly a library issue or a platform constraint (e.g. web app -> js). I don't see any reason why we need so many general purpose languages. Domain specific languages, sure. Why do we need so many general purpose languages? What exactly are the design constraints that are fundamentally incompatible between those languages? Case in point: the comment above you cites TCL, Javascript, MATLAB, R as examples of why we need many languages, when all of them are terrible language design. TCL has good built-in gui facilities, Javascript is built into browsers, MATLAB has many scientific libraries, R has many stats libraries. That's why they are used, not because the languages are any good.