By way of counter-example, check out this ICFP contest retrospective. Nikita is using clojure, a pretty niche language, but has built up incredible fluency with

By way of counter-example, check out this ICFP contest retrospective. Nikita is using clojure, a pretty niche language, but has built up incredible fluency with both the language and the ecosystem so that he can quickly throw out web scrapers and gui editors. Whereas I wouldn't be able to quickly solve those problems in any language after flitting around from ecosystem to ecosystem for 12 years. The thing with niche languages like Clojure is that you can leverage existing ecosystems(reducing the risk of getting stuck) unlike other languages that start from scratch. Probably the same for languages like F#, Kotlin and even Zig (using the C ecosystem). Of course, I found the article great with lots of good advice(ex: I still wouldn't use Clojure if Javascript can get the job done perfectly fine) so don't let this nitpick distract you or look the other way ;)