1. Complete compatibility layer with DirectX12, fuck everything else. No one is gonna rewrite their games in Metal to start at this point.
2. Writing drivers for a few hundred existing graphics cards.
(And the likely) 3. Partner with AMD or NVIDIA to create an intensely powerful per dollar line of proprietary graphics cards that obliterate the competition.
Apple seems to like an adaptive experience with certain tasks being best accomplished on certain devices, progressively upgrading features, as the devices support more complex user input. They generally execute this near perfectly everywhere _except_ gaming.
I think this is a neat announcement, but will likely fizzle. I really, really, wish Apple would take gaming seriously. At this point their platforms are primarily for content consumption, not creation, ignoring gaming comes off as sort of pompous (though maybe I'm the pompous one, ha).
Maybe with the upcoming modular Mac Pro this will be fixed, but I'm not gonna hold my breath.
* Apple TV is currently garbage too because the standard outta the box input device (remote) is horrible gaming. They need to ship a system with a sanctioned controller, or make an enclosure for iOS devices.