The author of the article below speculates that Steemit could be the one social network to unseat Facebook and rule the social network space. He goes in deep to explain himself. I think it's not even about killing Facebook. Steemit is a different beast in my humble opinion. Steemit introduced a new way for web content to actually breathe. It empowered users which is a first in many web circles. Steemit represents a paradigm shit that many will try to imitate and most likely fail. But the web is big enough. It can sure handle incumbents as well as the newly ambitious. Link to the article is below.
http://investorplace.com/2017/06/facebook-inc-fb-fear-social-media-kingslayer/#.WUGJgXXyuV4