Frankly, they need to make a stream for fresh material from less notable writers. There are so many politicians and big media types on Medium that start-ups are almost completely ignored. Thus they never get any traction.
I’m not saying that they should promote just any old thing. Rather that if the content is at least backed by facts (not alternative facts) then maybe the could give these writers a chance to get a little face time, and garner interest or a reader base.