A bit over a year ago, I tried writing on Medium, and what I found was no, not really anyway. Medium was putting the soft paywall on all of my posts, without me asking or benefiting from it other than hosting, though I could choose to make them hard paywalled. It was my impression at the time that they would only let you unpaywall your articles on there if you paid them that ransom, instead of every reader (by being a member). You could argue that the authors choose to post there when there are alternatives anyway, so it’s still on the authors (and I do).