Apple will likely stick to Safari based on their Webkit fork. Look at their stewardship of coreutils and the graphics stack on MacOS, its plain to see that they just don't care if MacOS is 5+ years behind the curve on features and performance if its not hurting battety life for most users.
Gaming on MacOS has become a much more limited experience than on Linux (blame Valve for this) or Windows. Apple wields a big stick with each of these choices, kneecaping HTML5 PWAs, pushing forward their own graphics stack (hence the crap OpenGL support and lack of Mantle support)