Epic doesn't want those users. It is not asking for any placement in the app store. It just wants it's own users who have iPhones to be able to access its software which it will funnel to them through their own channel. Apple contributes nothing to cultivate the gaming market overall. No marketing, no investment, no PR, no subsidation of the hardware etc. Apple simply gets in the way, making it harder, adding restrictions, invading Epic's customers privacy and then to add insult to injury takes a huge slice of the profits.