Um, yes Apple has final say over anything with their products. It is their proprietary product and if you want to build a business off of Apple’s back, you abide by the rules they set. Otherwise, find someone else’s product you can piggyback on. There is no monopoly in the repair market at all. Apple doesn’t even have to allow anyone to repair their product, they could require to have any of their products serviced themselves and that most certainly would be in their purchase terms and conditions. Again, if you as a customer don’t like that, don’t buy it and then later complain that you were somehow forced to not have any options. That’s just asinine.
Besides, you cannot survive just as an Apple repair shop, the margins are too low (or your prices would be too high). The shop has to sell other goods & services in order to have a viable business. As a business owner you should know these things before you enter the market. If you decide to still put all your eggs into one basket (Apple) and you don’t meet the requirements, then it’s all on you if things fail.