I'd argue that Play will circumvent this "hipster phase" issue for (at least) these three reasons:

(1) The ubiquity of the Java/JVM ecosystem paired with the interest in a alternative to Java will keep the functional JVM Langauges like Scala/Clojure in high demand.

(2) The Typesafe machine pushing Play (see http://blog.typesafe.com/typesafe-announces-14m-series-b-fin...).

(3) Scala is your best bet for a Statically Typed Functional JVM language. Also, we use Play 2.0 at the startup I develop for.

I also find that Play is pretty cool to work with. Gone are the days of having to use servlet containers for development.