And what is stopping someone distributing the app for ”free” in the App Store and then setting up a web based payment outside of the store.
I will give you an example
silicondust distribute the HDHomeRun Apps in the AppStores.
this allows to use the HDHomeRun Tuners to watch TV on your iPhone, iPad, AppleTV.
the App is free so no commission to Apple.
if however want to do recordings then have to buy a license which is done from the silicondust website who last time used have a 3rd Party payment system, (to whom they will pay a slice or commission for handling the transaction)
however Apple don’t see any money for this directly other then that I bought the iPad, iPhone, AppleTV.
works the same way on mobile devices running Android.
so now exactly why do developers HAVE to pay Apple commission. Silicondust aren’t and they don’t seem to have any issues with Apple on the AppStore of Google with it’s AppStore.
make a ”free” product that limited and put in AppStore. Unlock by going to website and buying.
they can simply setup own transaction payment system outside of the store and still comply with the AppStore requirements and don’t have to pay Apple any commission.
Silicon Dust didn’t need any regulation there either to do so and been using for years.
They are probably in the "reader" app exemption and Apple's rules are attempting to limit who is allowed to use that exemption. If your app doesn't qualify then you can't charge on your own website.
Apple also is trying to prevent linking to the website payment platform from within the app. This is to force users to leave the app, go to safari, then go back to the app manually - maybe typing in their password again. The EU and others are now clamping down on this because it is a "steering" measure designed not to make the user experience better but to make the experience of using a payment system other than the App Store worse.