Scala is a huge language, and many experienced developers have trouble using it effectively. You might learn a subset of Scala that works for you, but sooner or later you'll have to work with code written by others in a style that might be completely foreign. From what I've seen, Scala code ranges anywhere from Java syntax sugar to Haskell fanfic with libraries like scalaz.

Meanwhile, my team regularly hires coop students, and we never had to spend more than a couple of weeks training them to be productive in Clojure. Hiring and training people is simply not a real world problem when it comes to Clojure.