To play the devil's advocate: From an OOP perspective, lambdas are just syntactic sugar for a special form of objects. Regarding monads, we had smart pointers and the like in C++ already in the 1990s. Both concepts are orthogonal to mutability.
I'm convinced that imperative programming will endure alongside functional code, because being stateful is how the real world works, and most programs have to repeatedly interact with the real world over the course of their execution.
I'm convinced that imperative programming will endure alongside functional code, because being stateful is how the real world works, and most programs have to repeatedly interact with the real world over the course of their execution.