I'll pay you $100 per year for using your car. And I'll drive it for Uber and make a lot of money on it. Incase there is a repair, the cost is on you. Is that a fair deal?
That's a rather poor analogy, but in any case what does it matter? You are the one who gets to set the price.
The reason it's a poor analogy is that Apple doesn't provide all the support they do for altruistic reasons. They do that so that the hardware they want to sell you is a viable product and we all already pay for that through Apple's sizeable margins. I'm not complaining, I'm just stating the obvious.
Beyond that they should absolutely be able to provide additional services to run on that platform and be compensated for them, but the iPhone isn't a store. Neither is iOS.