In my opinion Haskell is just a much higher barrier to entry language. It's far harder to get into unless you are an experienced dev. This precludes adoption. We all know languages which make it simple to write (even if it ends up being a mess) win - aka javascript/python. The AI aspect is interesting, it's encouraging rust adoption since it lowers the barrier to entry. I suspect AI doesn't handle Haskell as well because it is so generic/abstract.

One other wrinkle is laziness by default. There are good reasons the language was done that way and strict isn't inherently better. In fact you'd give up a lot moving to a strict by default / laziness optional language. That said, laziness can make it hard to reason about performance. Experienced Haskell devs can do this but it still requires a lot of mental effort.

I suspect these two items are the primary ones. There are others. But I absolutely love the language even if I have never had the opportunity to use it professionally.