They are doing absolutely nothing to bring back gaming to Mac. Major developers (like Blizzard) who have been loyal to that user base for decades are giving up and it feels like Apple isn't even trying to figure out a solution.
Those reasons could be any number of things like not having native nvidia drivers, or lack of openGL support (which is completely deprecated in Mojave), etc...I'm happy to hear about their work on fortnite because currently my mac is overpowered for that game yet it is absolutely unplayable in its current state.
There are some games not available for MacOS but they seem to be less and less common. Almost everything now is cross platform, in part thanks to Unity making cross-platform games easy.
Most if not all of the Blizz games render using OpenGL. Heroes of the Storm used to have some experimental options to use Metal or OpenGL 4.1, however Blizzard got rid of them at some point. They seems to not be satisfied with Apple's drivers
They've been the biggest supporter of gaming on macos, and with them gone, the future is looking grim (for mac gamers - obviously a first world problem).