I’ve been writing on Medium for three and a half years.
Some of these reasons are very pragmatic for everyone, but he’s also got some business specific ones that touch on things many small businesses would want control over as well. He additionally points out some very subtle changes in media for people who are reaching out to niche audiences. Some of this is reminiscent to things Leo Laporte has spoken about in the past with respect to leaving television and cable to start a podcast network, except in that case there really wasn’t a huge amount of competing media, so instead of moving to silos (which didn’t exist at the time for his use case) he went straight to using his own platform.