Nothing is really missing, Haskell can do all of that.

I thought so. What's the reason for the PR problem, then?

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.

I can only speak from my own experience, but expressing a program as a composition of pure functions, where effects are carefully managed, is a challenging way of thinking at first. The imperative approach really is simpler to wrap one's head around _until you start worrying about correctness_. I think many developers never really care that deeply, so Haskell never appeals to them. You really do have to take a mathematical approach to program construction. I personally think that the mathematical perspective is liberating, but it's not an easy one to cultivate.