Although I don't monetize my maps, I do believe on the app where people are stealing my work they have a way to make money off of it so they post others works constantly to make a steady flow of money without having to do the backbreaking work. The worlds there on average get around 30,000 downloads, which is way more than I get on here for my maps. I have a map there with 58,000 downloads but here the same map may at the most get 5,000. You can make a lot of ad revenue posting maps like that daily.