The most comprehensive survey of what writers earn is conducted anually by the Authors’ Guild. Author incomes are down significantly. A big part of the problem is online piracy, much of which is promoted (and exploited) by major companies like Google and Paypal. Many of the websites that promoted stolen digital books that are still under copyright actually make money off of the books they’ve stolen, taking money directly from the pockets of the writers. Piracy is also a problem on Medium, unfortunately.