If you remember, the Applicative type class gives us an abstraction to define parallel computations. It was set against the Monad class, which is an abstraction to define sequential computational.
In the Type Classes section in Chapter 8, Basic Type Classes and Their Usage, we reasoned that Applicatives are needed to provide you with a primitive to define independent computational. Parallelism can also be modeled by the Applicative. However, it is precisely the idea of independence for motivating force behind this type class.
Parallelism and concurrency require a different approach. They give rise to problems that are not normally encountered in sequential programming, and these problems have their own techniques so that they can be solved in object-oriented programming. However, these techniques are even more error-prone and hard to reason about...