There is a reason why Haskell is not popular. But I don't think the impenetrable passages about Monads are the reason behind it. It is more about what you gain by adopting Haskell and powering through the impenetrable passages. If it is not blazing fast runtime performance and fast speed of development and maintainable code, then Haskell is pointless. As such, if there are those kind of benefits available, there is plenty of extra brainpower available among developers to comprehend passages.