I completely understand your frustration. And you sparked an article for me to write, which I will do today: Own Your Niche.
You have an interesting perspective here that adds value to medium. I say own it. What has helped me more than anything is the Tope Writer Status. If you are writing in your niche, tag it every time in that niche, you can earn this status which will make your articles show up in that tag. This has gained me more viewership than the curations have.
Write for BOTH your personal blog and Medium. I often take a truncated or slightly altered version of my Medium articles and use it for my personal blog. Like to your Medium on each personal blog and link your blog on every medium article. This has also helped me.
The number one way to be successful here on Medium is to write for multiple publications and gain followers from doing so. I am writing for 23 pubs now. Get in with the pubs, write things that pub would like and take it from there.
Give Medium a few months before you decide. See how it can support your efforts elsewhere. Above all, know your goals and work toward them — with or without Matthew’s support. Use those emails as a frustrating but MOTIVATING kick in the pants.
YOU can do this. Quality content every time and social interaction. I am cheering for you!