That said, I like the app store rules they can enforce like IAP - I just don't think they should be taking a cut. If they want to charge a flat one time fee of like $100 to publish then fine, but profit sharing seems wrong to me.
My worry is their aggressiveness in defending their tax will cause blow back that damages their ability to leverage their rules. A worse outcome is one where they keep the tax, but app devs are allowed around the rules. This is starting to happen (an admittedly tiny bit) by them being forced to allow links out to sign up off of the phone.
If they just forced people to use IAP for their user's benefit (easy cancellation, easy account subscription tracking and privacy, easy payment), but didn't take a cut that would be the best outcome for their users and it'd be an easier argument to win in the public eye.
That includes potentially changing their developer agreement to now require developers to meter and perhaps even audit external payments to submit Apple's commission.
Because they can no longer differentiate payments made independent of the app (because the anti-steering clauses are gone) this could result in required commission to apple in cases which it formerly was not required.
And most important, apps should have no restrictions whatsover to have payments inside their own app ecosystem!