will not solve issues with compositors not having it
Many compositors already have patches for explicit sync which should get merged fairly quickly.
graphical libraries not having it
Both Vulkan and OpenGL have support for explicit sync
apps not supporting it
Apps don't need to support it, they just need to use Vulkan and OpenGL, and they will handle it.
Wayland doesn't implement sync of any kind, they probably meant to say "the Wayland stack"
Wayland has a protocol specifically for explicit sync, it's as much a part of Wayland as pretty much anything else that's part of Wayland.
Nvidia is not the only driver that needs to implement explicit sync.
Mesa has already merged explicit sync support.
...is Mac gaming actually gaining ground? From listening to a friend of mine who has a Mac, it sounds like Mac gaming is going steadily backwards. Wine and similar doesn't work very well for them, and Mac compatibility is happening with fewer and fewer games. Game Porting Toolkit isn't really for end users, is it? Is there something else my friend is missing?