Yea so as a developer I pay two taxes: The first 30% goes to Apple, the next 30% goes to the government, now for every dollar my app sold for I make 49 cents.
now compare how many services you're getting for that 30%: a legal system, roads, schools, hospitals, an army to defend the nation you live in, in some countries healthcare etc etc...
now back to apple: for that 30% you're quite literally getting the permission to keep working.
Can I ask you something? Could you evaluate the storage/bandwidth price by using something like the S3 price calculator as a reference and stripe for payment processing?
It would be interesting to see how much is apple actually getting on top of publicly-available, practically retail prices.