That's actually explained in the video. Wales says that news media don't have the resources to produce high-quality output because the competition for clicks is so fierce. WikiTribune addresses this in two ways: First, they don't participate in said competition for clicks because they won't run on ads but donations. In other words, their customer is the reader who has an interest in quality. Second, they recruit citizen journalists who can help produce articles that a traditional news business would not be able to afford. Just paraphrasing. Watch the video.