I've always wondered about the same thing. I understand only high quality posts are hosted over there and readers love it. But what do the writers get? Is there a way to monetize your medium articles as a writer? Seems like there aren't any ads based on the medium articles i've read. Maybe some people just like doing it for free but still..
Other people write articles of certain projects or ICOs as away of getting paid in bounties... if am not wrong articles from medium are accepted by most bounties so long as you have a large audience so in one way or the other certain people still get something from writing certain articles