there could be a Medium-like platform to publish free stories thereby gaining an audience. But it would be up to each author to convince their audience to pay them for something, such as buy a book.
I don’t think it is easy to monetize using a model like Medium.
gdoc
11

To play devil’s advocate.. isn’t Medium already such a platform? What would be the difference in a fiction model? Or is the thought that the main benefit would be the narrowing of the field, so “everything else” that is not fiction would not get in the way?