I'm not sure i fully agree with the analogy. John Lewis pay a different rent (again presumably) based on the more desirable location, but it's also reasonable

I'm not sure i fully agree with the analogy. John Lewis pay a different rent (again presumably) based on the more desirable location, but it's also reasonable to assume their payment provider is the same. In this case, I would argue that Apple have the monopoly on the App Store, which is fine if they are reasonable about it. However, there's no optionality on the payment processor: they insist it's them and take 30% (from what I've read; not actually an iOS dev). Would it not be more reasonable for them to charge a small revenue fee (rent) and allow you to choose a payment provider? They could audit the payment provider to achieve the security features that they seem to be presenting as an excuse for their charges.