The "Generalist" badge is described as "Provided non-wiki answers of 15 total score in 20 of top 40 tags." I assume that the top 40 tags are the first forty on the tag list.
By my reckoning, there are 29 of the top 40 tags for which I've provided answers with a total score of 15 or more; I don't think I've posted any wiki answers. I'm sure several of the other higher-rep users have also done this. But nobody has been awarded the Generalist badge. Why not?