Scala has jokingly been called Hascalator [1], but not everyone who is "ready" to make the leap to Haskell can actually do it (existing work tied to JVM, dependencies on JVM libraries, etc.) or wants to do it (better ability to reason about resource usage, familiarity with tooling, etc.).
I do write in Haskell where it is appropriate (for fun, or if I want to prototype some complex domain model). Otherwise, I am quite happy with Scala. :)
[1] https://twitter.com/yakticus/status/577663763991564288