There are a number of other languages that fit the bill: F#, OCaml, and ATS, for starters. Shen (the newest version of Qi) was released last week so there's that too, if you're into Lisp.
In the enterprise, there are no other languages that fit the bill besides Scala. You underestimate just how much java code exists out there in any commercial bank, IB, big corp., yada yada. Its an order of magnitude more than your wildest imagination. Sad, but true. Now, how are you going to migrate all of that to Scala ? Easy - just do nothing for the legacy non-buggy stuff, write any new functionality in scala, and continue bugfixing legacy buggy java code in java. That's the only alternative. Not migrating to scala is gradually becoming a non-option. Too many advantages over java to even begin listing at this point.
Now if you are an MS shop, its a different story. And ofcourse none of this applies to startups, who can use pretty much whatever they want.
