We at Brenwill, developers of MoltenVK, have received user interest in GLFW supporting Vulkan on macOS (and iOS) by linking to MoltenVK.

If there is GLFW community interest in this, we'd be happy to provide whatever support and advice we can to anyone in the GLFW development community who wishes to update GLFW to support Vulkan on macOS via MoltenVK.

...Bill