> I have never ever seen a job ad asking for Haskell
I see those occasionally, even here, on HN: in those "who's hiring" threads, and a few linked from this thread. But they tend to be odd: working on astrology, cryptocurrencies/NFTs/etc, or other unfortunate conditions coming along with it.
I'm also writing in Haskell at work, though that started as a Perl job. But for the reason mentioned above, I'm not sure if it's a good idea to look for a Haskell job, even if you want to write in it: restricting jobs to just Haskell certainly makes it much harder to find openings in places that work on something sensible/useful, and satisfying other requirements (especially if you also include ones like remote work). Unless one is particularly focused on just the process and not on the result, using awkward technologies to achieve useful goals must be preferable to using nice technologies to achieve something of a dubious value.