We saw how it took 10+ years and a dominating market position for Apple to show their claws with controlling 3rd parties with the App Store. Make no doubt that once a significant portion of the market uses Apple hardware or services for transactions, that they will want control and a cut of the transaction.
Notice how they say: partner-enabled iOS app
This means Apple has to endorse each 3rd party, and they remain under Apple's control just like app developers.