I found Haskell too difficult. They focus on a specific niche, so they won't be a mainstay programming language anyway, but even then when you ask people what are the real innovations or success stories per given year, say, 2025 or 2026, they almost never mention Haskell.
I don't mean to sound elitist, but in a way, Haskell's difficulty is kind of the point of the language.
The thing that's so elegant about Haskell is that it allows you to express programmatic constructs at a very abstract level. Abstraction is almost by definition difficult to grasp. That's why it takes a decade and a half for (most) people to go from arithmetic to calculus.
On the other hand, the language is already 35 years old and people still use it! Many other languages have died in the meantime.