Disclaimer:
I've never used Temu or the Amazon app, but I'm assuming they don't apply a 30% surcharge on physical goods on iOS.
Patreon is in this weird gray area because you kinda-sorta are getting digital goods delivered via the Patreon app, depending on how you look at it. And obviously if there's a way that Apple can squint and say it falls under their purview, they will...
This assumption starts breaking as internet becomes more ubiquitous and for anything really outside gaming coins. Example, for every additional Spotify subscriber, Spotify needs to pay music producers as well. The economics is now very close to physical goods being sold in Temu or Amazon.
I can name more than 1 competitor to Amazon.
If there is actual competition in a market, the surplus generated by economic transactions is more fairly distributed by the participants in the transaction. When there is competition, businesses also need to compete and improve their products to drive efficiencies (for better margins) and to make the product more attractive to buyers.
Because Apple is in a monopoly position, the only way to sell to Apple device users is via their app store. If you want to sell on their App store you need to give apple 30% of revenue. To be clear, Apple does not provide 30% of the value here. This 30% is pure rent seeking, once the app is installed Apple provides 0 value.
If you really wanted to equate Apple and Amazon, it would be like Amazon taking 30% of the initial transaction then forcing all revenue generated from products sold on Amazon to give 30% of revenue in perpetuity to them.
My entire point is that this distinction seems increasingly arbitrary on Apple's part and is perhaps driven by the expected outrage if they tried to pull the same stunt with retailers like Amazon or Temu.
which is pretty good evidence that society should pass a law to disallow apple from doing it (rather than let them pick and choose to charge a subset small enough to bypass public outrage, but still rake in an undeserved tax on apple device users)!
Yet there is also another competitor to Apple on iOS devices. It is called the web. Patreon in no way owes money to Apple if the end user fires up a web browser on their phone and makes their contribution through the website. Argue all that you want about convenience, and you're probably right on that front, but it is a way to circumvent Apple to have more of your contribution delivered to the intended recipient.
In the end, the decision of iOS users to support Apple's practices are at issue here. Sometimes you just have to say no using whatever means are at your disposal.