I am very impressed by the calibre of people posting scientific related posts on Steemit, and I think many of the models proposed all seem to suffer from the problems that you mentioned (or at least haven't addressed them adequately). I can't see that the blockchain system can be used to solve these issues because it is only a means of decentralizing content and its creation (like Wikipedia), but perhaps it could encourage scientists to be better communicators to the general public and also other scientists from around the world?