Yeah, you can emulate laziness at the library level with iterators, coroutines and whatnot, but it always comes with a certain API friction (some readers might be familiar with the “colored functions” analogy [1]) compared to Haskell’s approach that takes laziness to the extreme.
I was really hoping that article was going to start talking about effect systems. They're so cool! They make it possible to have many different function colors without it being a huge chore. They can be thought of as a more-ergonomic generalization of monads.