I think the other thing that people are missing here in regards to gaming is that it will go both ways. Imagine a desktop platform that is also your mobile platform. If games that have "A" level of quality come to macOS (perhaps upwards of AAA, but CoD I don't think will be missed by most mac/iOS users), they'll also be able to be used on iOS. You could have "cross platform" iOS/macOS games that are AAA and allow you to pickup on one and play on the other. There isn't another system that is close to that other than the Switch. The benefit is that more iPhones are sold in a year than all three current gen consoles from launch to current date combined. Meaning that if done correctly, this could allow devs to leverage $60 phone games that can then be played on desktop etc. All it will require is a controller, of which Apple already has a built in SDK for. The only other area necessary is having powerful enough hardware and/or different graphics settings on different levels of hardware.
That can be a double edged sword though. Two problems it can potentially have:
1) If the games are being designed for both platforms, that means lowest common denominator. So you get games that aren't as good and don't take full advantage of the desktop because they also want to run on mobile. That isn't a killer issue... but it is an issue. For two games that suffered form that see Xcom and Shadowrun. Both were designed to run on mobile, and had mobile versions released, and both had limitations they otherwise wouldn't have because of it that got lifted later. You find Shadowrun Hongkong has much more detailed and larger levels because they didn't have to hit the same memory targets to make it work on mobile. Likewise Xcom 2 sees was more of a jump than you'd expect in graphics and interface design because there wasn't a mobile target.
2) Mobile games can poison the well. Let's face it: The mobile gaming market is utter shit. There are so few good titles they are almost entirely drowned out with low effort clones, aggressive pay-to-win bullshit and so on. It is part of why the switch has been able to succeed, because the tablet/mobile market is so bad that many gamers who want to game on the go want something with better games. That could happen if they come to the desktop. The large amount of crap drowns out the good stuff, and developers of it are discouraged and go elsewhere.