In non-lazy languages you would need to implement laziness to manage composing functions and have good performance.
An example being take 5 . filter ...
If evaluation wasn't lazy you would run take 5, return the result to filter and so on.
In the languages I use (Scala, Ruby) it's already done, Rust is using iterators which are lazy too. None of those languages are "lazy" in Haskell sense.
