I agree there are some costs, but I think that the amount Apple feels entitled to take is still distasteful. As there is no competition, the pricing is quite high.
That "no competition" stance requires defining that Apple has a monopoly on selling their own products, which is true, but fairly useless. In the larger market in which iOS is a participant, they have quite a competitor in Google, with a number of also-rans clawing for attention.
