Why doesn't Function2 have an andThen method?

I can't speak as to why Function2 doesn't supply and andThen, but Scalaz defines Functor instances for functions of various arities where map is equivalent to andThen, meaning you could write

val multiplyAndDouble = multiply map double

I have just noticed it is easy to work around with the following:

val multiplyAndDouble = multiply.tupled andThen double
val res = multiplyAndDouble(1, 3) // res = 6