Seeing that most major subscription services on the App Store are already forcing users to subscribe outside of the App Store, Apple isn’t getting a cut of subscriptions from the most popular service.
How many apps require a subscription and cannot be a web app because of limitations of Safari?
How many paid apps would be websites if it weren’t for limitations of Safari?
The moment you offer in-app payment, apple gets a cut. This goes as far as not allowing apps that link to payment outside of the appstore's payment system.
There is a huge number of cordova apps out there. These are webapps inside a native wrapper, to access exactly those features that are crippled in safari. Reliable storage, push notifications, and not much more.
ACloudGuru does not allow you to pay for subscriptions via in app purchases, Udemy allows both. A company can decide whether it is right for their business model to allow in app purchases exclusively or along side their own payment options.
Hulu for instance allows in app purchases for the regular Hulu service but not Hulu Live
How many apps require a subscription and cannot be a web app because of limitations of Safari?
How many paid apps would be websites if it weren’t for limitations of Safari?