I'm not proposing a unified theory of Google's choices. Google reader is more easily explained by other factors, specifically that it didn't fit nicely into the G+ push by Google and was not otherwise monetized by ads in any significant way at that point. Somewhat tragically, had they built a content-oriented social network around Reader instead of an ill-conceived integration to G+, it would have been more readily monetized and improved Google's chances of success in Social.