ProtonMail charges a lot for their services and they have no problem with that. I don't see why Apple shouldn't get their cut.
>Yen says the company was forced to raise its prices since the 30-percent commission that Apple takes completely ate away ProtonMail's profit margins.
Now multiply the 30% increase times every (paid) app on your phone.
(NB: I'm not against Apple making healthy money from the App store but 30% is just gouging IMHO)