It also overlooks one of the hardest parts of building a community site like emacswiki, which is, well, building the community!
Anyone can install mediawiki. Not many people will be able to put the time and effort that the emacswiki community has to keep a site going.
About the only part of the article that I agree with is that it's time to start moving code off the wiki. Though this isn't a "deadline" type problem, it should simply be discouraged going forward and packages of interest should start migrating.