You raise some interesting points. At nearly 1.7K followers, I can tell you the difference between 300 and 1600 is almost negligible. Most of my traffic seems to come from new readers, and that can be good, because Medium pays better for new/rare readers than those who hang on Medium all day every day. Being both editor and writer in publications, I can also tell you that even huge publication's aren't necessarily king and queen-makers. Getting access to an extra 400.000 publication followers can still result in a low traffic article, simply because... algorythms and whatnot. Moral of all this? Keep writing what you love writing about. The rest will happen one way or another. The world thanks you for writing. :)