Are they, though?
I think the way mainstream publications have been handled recently is a huge blow to the idea of Medium as an open, democratic platform for sharing content.
Mainstream publications are paid upfront regardless of how their articles perform. They get prime space on the home page even when they aren’t generating significant engagement. They are also allowed to include a call to action in their posts, as Erika Sauter pointed out, while regular users are required to remove theirs.
I get the impression that Medium is undervaluing the work of the users who make this platform what it is, while betting on the off-chance that outsiders will become members just to have yet another place where they could read a handful of articles from NYT and CNN. In the meantime, we have popular, long-established Medium publications like P.S. I Love You trying to join the Medium Partner Program and having the door shut on their faces.
I’m not sure if this decision was based on any research done by Medium staff, but my gut feeling tells me they are dead wrong.