I see two thinks to distinguish in your discourse. First the hiring pool. I don't see any consensus here. If you take Haskell for example there are so many tale

I see two thinks to distinguish in your discourse. First the hiring pool. I don't see any consensus here. If you take Haskell for example there are so many talented devs knowing the language without opportunity to use it professionally that they will rush on the first job offer. Now if you take Clojure it may be different. There may be enough positions occupied to make it hard to hire. I don't know, so I'm speculating. In general a good dev should be able to pick up a new language in a few months and in my opinion the potential hiring problem may be exaggerated? Your second point is about platforms. A FP language hosted on a popular platform has a lot to gain. That's the Clojure story. Rich Hickey tried different solutions / languages before but only Clojure was successful enough. Because it's tied to the JVM. But... nowadays most popular FP languages are hosted on a popular platform (JS/Web, JVM, .Net) so if a FP language builts a community that is big enough (no need to be big like Python) it will be sustainable. Last comment: if you think about sustainability on the very long term, such as COBOL projects, then choosing the default language of the platform (JavaScript for the web, Java for the JVM etc) may be wise (because the platform is more likely to die after the other languages). The truth is that most software project don't have such a long life so it should be only one criteria among other for the choice. So to conclude given a good choice for a platform (BEAM for distributed systems for example) I think languages do matter, because they offer different trade-offs (less state bugs with FP languages for example).