NO DEAD END. “Specialization is not a certain ‘dead-end’ from an evolutionary perspective. First, transition from specialization to generalization is possible and even prevalent in certain ecological contexts. Second, specialization in traits related to foraging or reproduction can be associated with increased evolutionary success of some specialist clades, especially in specialist clades that experience greater transition rates to different specialist states.”
http://rspb.royalsocietypublishing.org/content/281/1795/20142004.short