Really nice readable design that gets out of the way. And I can know from the URL that the page I'm going to will have really nice readable design that gets out of the way. It shouldn't be hard, but so many sites manage to get it wrong.
Maybe that's on reason they are struggling - more and more sites are getting it right now. I used to use reader mode in my browser all the time and I find I use rarely use it anymore.
If Medium were to go away, I suspect those links would just lead to a different site. What value does Medium add?