Based on what arguments?

If Apple’s cut were 12% and Epic and Microsoft now charged 6%, would you claim “The 12% that Apple charges seems about right IMO”?

Yep, if someone is able to maintain above market level profits for so long it's usually a sign of monopolistic pricing. That's not necessarily bad, but in Apples case it's just double dipping on their monopolistic position and is clearly a drain on the market with no benefit. They have the same incentives to invest in R&D and support the ecosystem on the insane HW margins alone, I'd be willing to bet their dev budget doesn't change at all if this change in rate was made.

But how do you know 12% is about right, and not 10%, 2%, …

Also, Apple will claim they have a better product that warrants higher margins. Data from independent parties shows that they attract more users willing to pay for apps, and developers aren’t leaving en masse for Android.

>Also, Apple will claim they have a better product that warrants higher margins.

And this argument is fine in the hardware market because they have competition, it's efficiency monopoly - that's why I said it's not always bad.

However their app store controlls access to 50% of US market (even more by revenue) simply because it comes as the only option and the consumers can't unbundle it. If they had competition on the platform (different stores/distribution methods) - you wouldn't have to say what % is right, the market would decide the value added by their app store/payment methods.