All this hinges on the fact that functional languages are only now being appreciated: functional languages seem to be popping up like daisies now either via stand-alone languages such as F#, multiparadigm languages or even in OOP languages (I believe I read somewhere that C# is integrating ideas from the functional paradigm). Still I can't pretend that any functional language has so far become as remotely popular as say Java or C++. Due to this the work done on functional programming and games is quite a niche area which is often explored to do a fun project while learning a language.