The primary purpose of the 30% fee is not payment processing or delivering updates, it is the licensing fee for the use of Apple's intellectual property (SDKs and developer tools).
The primary purpose of the 30% is to get 30% of money. If apple could get away with 60 they would. Apple more than pays for the SDK development just with their cut of child casino apps they sell. Everything else is just free cash.
And? You can say the same about pretty much anyone that sells anything. Why does a restaurant charge $15 for a cocktail that costs them 50 cents to make?
