Agreed, there are many, many publicly available methodologies to rate language popularity, none of which are great, but this one seems especially odd.

It'd be nice to see a time-lapse of the TIOBE index from 2009 to 2013: http://www.tiobe.com/content/paperinfo/tpci/index.html

Or any of these dozen other measures (including mentions on delicious, or IRC): http://www.langpop.com/

Or employer challenges posted on CodeEval: http://visual.ly/most-popular-programming-languages-2013

That said, the underlying thesis may be true that more projects today require more languages, hard to say.