The Decline of Wikipedia: Even As More People Than Ever Rely on It, Fewer People Create It:

Yet it may be unable to get much closer to its lofty goal of compiling all human knowledge. 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.