Apple is not making any effort for Mac gaming because it does not make them any money. Steam is working a lot harder to make games work on Linux, than Apple is working to make games playable on MacOS.
In all seriousness, I dont even know why why developers even bother to release a Mac version unless the game engine software has a button that says "Export to Mac format."
The developers will bother to release games if there is money in it (user buying the games OR apple subsidizing), there are 2 big issues with Mac gaming :
1) Windows is the monopoly of the PC world , they own a proprietary graphics API (DirectX) that ALL the games in the PC world use , the same API is used on the Xbox as well , when you write and optimize (which is something ppl miss when they look at a game development) you do it for your major platforms , today it means everyone write for DX and optimize for DX , some might port a game to Metal, but do they optimize for Metal ?
2) Gaming studios being bought up by the biggest players , mainly Microsoft , making it even harder to make games for Mac as they have a higher level strategy to keep games "exclusive" .
But not all is doom and gloom , if the Macs will gain better GPU`s in the more popular Macs , it will make the target audience bigger , which in turn will make some of the developers more incentivized to get their games on Metal/Mac.
If I am a game developer and I see a platform with no games , I can see it in 2 ways :
1) this is a dead platform for gaming , why would I put my game there ? it will cost me money to bring it there!
2) this is a dead platform for gaming - > BIG opportunity for me as I have no competition !! if I put my game there ill get much more interest , publicity and a more "starved" consumer base.
If you get a popular shooter for example (Overwatch for example), then this specific shooter will be the only one in the Mac world , so 100% for the Mac gamers looking for a shooter will buy it as they don't have anything else to buy.
Path of exile Is going to be native for Macs/Metal in the upcoming months (hoping POE 2 will be ready for Metal) , while it looks like Blizzard are leaving Mac in the Diablo world , this means that if you are in for an APRG , your only option is POE (great game by the way) on the Mac , this makes it lucrative for GGG.