Not sure if it has been mentioned yet, but I think the main reason why this title failed is the title. Most people probably never heard of "yerba mate", so to them, the title sounds like some kind of weird mating simulator.

You can verify this by comparing the sales by country to the number of searches for the term "yerba mate" by country: https://trends.google.com/trends/explore?q=yerba%20mate The distributions are very similar.