The challenge (as always) is accessibility and discoverability. The functionality is all there.
And that's the challenge that actually matters, and is more or less insurmountable on iOS.
I'm not making a judgement on right or wrong, but I see many people just thinking about infrastructure and not realizing Apple sees iOS user base as one that would not exist without them. And, they want to get paid for access.
This is what happens on consoles today. Apple views the iPhone as a closed and complete ecosystem where licensees are allowed to write apps - like a console. The hardware, OS, and App Store are viewed as a single entity and not distinct.
Not saying I agree, but it's important to understand Apple's argument. Given the ruling from the Epic case I think Apple will win the majority of any action taken against the AppStore (not a monopoly, business terms are irrelevant). IMO where Apple is vulnerable is interop like with messaging. I can only guess Apple's lawyers think the same, hence Apple's fairly recent push into RCS.
Except no, actually, it isn't. Neither Xbox nor PlayStation attempt to collect a 30% royalty from any of the streaming apps nor block them from steering.
Consoles have a significantly more harmonious relationship with the developers, whereas Apple's is drastically more abusive. This is not an insignificant difference, both morally and legally.
Patreon does.
I'm inclined to think the "write off the iOS app entirely" option was one of the very very first things they pondered, and the odds are that it's pretty clear that was going to be a very, very expensive option.
Patreon works fine in a web browser.