The difference being of course, on Apple's stranglehold on its customers. 30% either way, app developers know that Apple users are always willing to pay more and Apple knows this, too. That's why many apps only target iOS.
Besides the income from services within Apple's apps: they could take 30% of an app's purchase price (which is still not justified tbh, the app store can't be _that_ expensive to run), but how do they justify trying to take a percentage of a subscription (like Spotify, Netflix etc) when they have nothing to do with it?
That would be like Apple being able to take a portion of banking fees from me because I have my bank's app installed on my phone (and the bank takes fees), which Apple doesn't do of course because as big as they are, you do not fuck with banks.
[0] https://arstechnica.com/tech-policy/2022/02/apple-shocks-ios...