I am not going into the legality of this entire tussle, but I would say that this is the end of Apple as a major gaming platform. To be honest there wasn't much on Mac OS to begin with, iOS had something going on for them in mobile market; but this would be the end of any potential Apple had in the gaming market.
In the long term I think it would hurt Apple more than Epic.
In the long term I think it would hurt Apple more than Epic.