I've been distributing software since long before the App Store existed. I very much know how it used to work and how it works right now, and no business I've ever worked at has ever paid 30% of gross revenue to anyone. Even now we don't pay, because we refuse to use in app purchase.
We prefer to make our app significantly worse by forcing users to already create an account (on our website) before they download the app. If they download without having already signed up, they can't use the app and won't be given any information about how to sign up (because that's against the rules).
As for "access to 1.3B users"... our website is available to anyone via a google search. That's 4.3B users. We have no problems finding new users without paying a cent. And no customer has ever complained or hesitated to pay us directly.