Tom Simonite wrote a very interesting investigative piece called The Decline of Wikipedia: Even As More People Than Ever Rely on It, Fewer People Create It:

Wikipedia’s community built a system and resource unique in the history of civilization. It proved a worthy, perhaps fatal, match for conventional ways of building encyclopedias. But that community also constructed barriers that deter the newcomers needed to finish the job. Perhaps it was too much to expect that a crowd of Internet strangers would truly democratize knowledge. Today’s Wikipedia, even with its middling quality and poor representation of the world’s diversity, could be the best encyclopedia we will get.

The article also reminds me of one of the best episodes of Hypercritical ever, called Marked for Deletion. John Siracusa goes into a highly entertaining and informative tirade about the problems with Wikipedia, which is well worth the listen.