27% is absurdly high, for sure, but you seem to be arguing from a position that it should be free...?
The other large discussion thread has already been linked with more specifics. The very short version is that Apple has been arguing the fees are to run their services, and the commission has historically been a convenient way to collect them. This is them collecting those fees outside of their payment systems, because legally they have to allow such a thing.
So you could release an app for "free" on the app store, and require side channel payment to really use it. You're just going to have to pay for the quotation marks.
only if you want to release your app on Apple's platform; you're free to release it on Android, Windows, Linux, Unreal, etc., each of which has their own set of fees (or none)
Apple charges 30% if you do choose. Epic charges 5%.
Apple argues that what you're paying for includes SDKs. Epic does too.
Yes, you are. If you're writing a mobile app, you HAVE to support iOS or go bankrupt.
There are no other options.
Welcome to the land of monopolies.
you are forced to pay Epic 5% of sales (if your game makes more than $1 million), so pretty much like Apple (fees are lower of course)
And I'm not arguing that apple needs to reduce the fee. They can charge whatever they want for their IAP system. But, other companies that have software/services that are cross-platform, should be allowed to use their own payment processors without paying additional fees to apple imo. Apple should be able to put up the message that hey, you're leaving our ecosystem, you're on your own, blah blah. But I don't see a reason why they should also get a cut at that point.
Nothing similar is the case for Unity vs Unreal; the customer base is the same either way.
And with Epic, you don't have a choice if you want to use the Unreal Engine. How can this argument go on and on and on? All your arguments can be used in reverse with the Apple competitors. Nobody is forced into anything, especially not developers.