You "cheated" by using zip. You can't easily implement zip using only internal iterators but you easily can using external iterators. If you look at a slightly different problem that doesn't precisely fit the special case of zip you'll see the difficulty involved with using internal iterators.
Haskell typically uses internal iterators, but because it's lazy many composition strategies are more straightforward. Rust is strict, however, so the same techniques don't apply.
There is no general zip for every Traversable, though there is one for every Applicative with a suitable instance (like the ZipList wrapper for lists): liftA2 (,)
The reason is that you need to operate on multiple containers at once and that is what Applicative's (<*>) provides, while Traversable only requires Functor and can therefore only traverse one container at a time.
So what Haskell has is just internal iteration, but we have another interface for internal iteration on multiple containers that allows zip to be implemented easily.
