All programming paradigms have useful abstractions to offer. Eventually, they will all come together. Object orientation is great, until one overdoes it in design pattern hell. Likewise with functional programming. There are great many ideas in academic programming languages that will be made more accessible and integrated into mainstream programming languages. Functional programming is a dead end only in the sense SmallTalk was a dead end. People may not use SmallTalk much today, but its ideas live on in nearly every language we use today. Functional programming is here to stay. It won't replace imperative and object-oriented programming, but will add to them.
First and foremost, programming languages are for people, not computers. So if regular programmers who form the bulk of the workforce can't grok them, the languages need to be fixed, not people. Haskell is too hard for most. But it has many wonderful ideas that can be distilled into simpler forms and adopted and integrated elsewhere. Python got list comprehensions from it and perhaps the indentation.
C# is absorbing some features and Java is doing that less elegantly. Scala is a good balance and has already established itself. But people still find the type system complicated. So there are attempts to bring forth a simpler Scala - Kotlin, Ceylon etc.
We all agree that things like compact syntax, first order functions, lambdas, streams, type inference etc that functional languages pioneered, belong in every language. We still haven't sorted out how to make more advanced type systems, provability, strict programming without side effects etc more approachable. We should not need to have this much trouble explaining what a monad is or isn't. We'll get there, eventually.