Gaming on the Mac was basically dead and will be revived with Apple Silicon, I believe. Even the MacBook Air now has enough power to run modern games smoothly, and more powerful models are to follow. A considerable amount of iOS games are suddenly playable on the new Macs, too. And yes, native support for Apple Silicon and Metal is clearly the way forward.
I just ran Kerbal Space Program on the Air, in addition to being smooth and having no discernible lag. Htop says it's only using half of one core.. and the laptop isn't even heating up.
This is the dream laptop. It's the one product that is 5 years ahead of everyone else, like the iPhone 4.
I don't believe the main problem with gaming on mac was the architecture or their anaemic graphic cards but rather their non-standard mac-only graphics API (metal), their deprecation of OpenGL, spotty support of Vulkan (if any) and removal of 32-bit support (for older games). The first three are not really a problem for big engine makers, as they can afford to implement additional backends but it is an issue for smaller studios and indie makers. 32-bit support is probably going to be less important (unless Rosetta can also translate x86 only code). It's good that they packed a decent graphics subsystem in their new chips but that's only part of the solution.
I believe their main concern is to bring iOS games to macOS rather than bring new games into the platform. Let's be realists here, iOS games bring in the cash. If they can run it in another form factor with potentially better graphics then even more money in the long run.
Metal doesn't get enough hate for how awful and idiosyncratic it is. If you want to remain cross platform and support Metal you're so severely restricted that the best you can hope for is to just special case a bunch of features for non-Apple machines and not support them at all on Mac. It really feels like Apple wanted to kill gaming on Macs entirely. I understand that they want to maintain control over their own graphics stack, but for this to work the stack has to be better than the competition and that's not the case here at all.
For some indication, check out a lot of issue threads for WebGPU (the Rust cross platform graphics library). Many, many features need to be restricted or put behind feature flags due to either lack of Metal support, or Metal having bizarre restrictions compared to other platforms. As a random example, border color is limited to 2 or 3 colors for Metal, and has no restrictions at all for anything else. There are also entire features (like geometry shaders) missing from Metal; for many common usecases you can replicate the functionality with something else, but usually not in a way that easily translates to any of the other APIs (and pretty much nobody on Earth writes games just targeting Macs).
Hence, the easiest thing to do for most games is to just drop Mac support and not worry about it. IMO that's the biggest reason by far why people stopped bothering to port new games to Mac; between not updating OpenGL past 4.1 at best and Metal being so idiosyncratic, it's just not worth it, and since people have learned gaming on Macs sucks (largely because of the outdated and idiosyncratic APIs), most people who want to play games on a Mac have just been installing Windows anyway.
This is all not even to mention that Mac laptops tend to have far too high a resolution for the onboard GPU to perform well for any but the most rudimentary games; hopefully this has been addressed with the M1 batch having a much more powerful GPU. But the issues with Metal remain and will continue to remain until Apple either fixes Metal to make it a more Vulkan-like target, or adds really good Vulkan support.
