All of that being said, the study of language is very important, and the differences that exist should be recorded for scientific study. Maybe it even makes sense to preserve the real outlying communities (http://www.amazon.com/Dont-Sleep-There-Are-Snakes/dp/0307386...) by forcibly cutting them off from the global economy.
But major languages (English, Spanish, Portuguese) are redundant standards that should be consolidated ASAP.
There's quite a bit about the language, but the backstory of Daniel going over as a missionary and losing his faith (and family) while trying to convert a happy people in no need of religion is stunning.
It seems a bit naive to say "every story in the world" when they analyzed only "thousands of novels" -- this doesn't even mention what languages they analyzed. I could imagine many Greek-influenced cultures (e.g. "the West") having similar archetypes by virtue of a common ancestor. Language analysis tools for CJK aren't, as far as I know, as advanced, so I can imagine a lot of stories from those languages being left out as well.
The reason I bring this up is that I'm reading a book called "Don't Sleep, There Are Snakes," [1] which is about a remote tribe of people in the Amazon jungle called the Pirahã. [2]
One of the most stunning points in the book is that their culture is such that all stories told by native Pirahã are based on first-person experience. When a Pirahã dies, their stories are not passed on or retold. Due to this, there's also no need to record past stories, orally or otherwise.
This kind of study would obviously exclude stories from that kind of culture and seems a bit narrow-minded: "everything I looked at says A, so EVERYTHING must be A."
[1] https://www.amazon.com/dp/0307386120
[2] https://en.wikipedia.org/wiki/Pirah%C3%A3