It's because Apple's actual costs are pretty much fixed (storage, bandwidth, ...) so clearly on a low price / many customer scenario it seems fairer.

That's why a per usage pricing would be fairer. And yes, the app having one thousand $10 purchases would pay way more than the app having a single $10000 purchase, but that's the point.

But for Spotify or other apps that sell content Apple is not providing storage, bandwidth, or anything else. They do provide payment processing, but it's common for that to be a small percentage of purchase price already (e.g. ~1-2% for credit cards).

> But for Spotify or other apps that sell content Apple is not providing storage, bandwidth, or anything else.

Indeed, I missed that layer when answering you. That's makes it even worse and unfair.

> They do provide payment processing, but it's common for that to be a small percentage of purchase price already (e.g. ~1-2% for credit cards).

And working with Visa doesn't stop you from offering Mastercard or Paypal or others. Apple mandates you use them.

>e.g. ~1-2% for credit cards

It's capped in the EU - 0.3% for credit card, 0.2% for debit ones. That fee includes all the risks of chargebacks and fraud processing.