I've written about this. I have 7.6K followers and make around $400 a month but it can vary greatly. I have to hit one or two semi-semi-viral articles (1 to 2K reads) to make that much. I write 5-6 articles a week. I sometimes wonder if SEO has something to do with it, but despite copious musings I have yet to crack the code (which doesn't stop me from writing articles like "I cracked the Medium code" LOL).