The thirty percent is a common misconception.

That’s only true for one time payments. Most apps today are subscriptions, which are 30% the first year, and then 15% for subsequent years.

Small developers making less than $1 million per year can pay 15% for in-app purchases/

There are also apps exempt from any fee.

Nor is it just “for the honor of”. That fee covers hosting, billing and collecting subscriptions, fraud prevention, currency conversions, advertising, free development system, free training, and a tremendous amount of technical support.

See https://appleinsider.com/articles/23/01/08/the-cost-of-doing-business-apples-app-store-fees-explained