Why do the merchandise sales not count? Are they not a product of her creative writing? Many webnovelists sell merch. One of my favourite webnovelists semi-recently hired an editor, would that disqualify them?
I’m a little confused on how you are defining the conditions. If the artist can only count their personal contributions than I don’t think it is possible in any sense. No person no matter how hard working or talented can personally generate a billion in profit.