The conclusion you made may be wrong. You imply that all these $9 apps convert more than a handful of people. But if they convert the same your friend already a

The conclusion you made may be wrong. You imply that all these $9 apps convert more than a handful of people. But if they convert the same your friend already applied successfully the „charge more“ concept as (s)he is getting more from every subscriber. The $9 app needs to have 34 times more subscribers to be more successfull. It‘s a very niche product, it‘s not easy to say which one is selling for better the value.