Apple has to pay for these somehow. They can either get the money by charging more for each iPhone or they can get the money from the real end-users of these products: Developers.
But Apple are choosing to maintain XCode, not as a charity, but to make money selling phones -- $250 billion last year. It's not like they aren't getting paid for it…
What is Apple spending 7.5 billion USD on such that they'd have to raise the price of iPhones? They have multiple other revenue sources as well, like developer program fees. None of those cover their costs either? Are you suggesting they're selling phones at a loss?