macOS has barely functional OpenGL support and no Vulkan support at all. Most of the value of Proton comes from the DXVK project (aside from Wine itself), which

macOS has barely functional OpenGL support and no Vulkan support at all. Most of the value of Proton comes from the DXVK project (aside from Wine itself), which is a D3D->Vulkan wrapper. In theory it could be combined with MoltenVK, which wraps Vulkan to Apples Metal API. Chaining two graphics wrappers like that is probably fairly error prone and the losses in performance are likely too high to make it applicable for video games. Additionally ever since Apple ditched 32 bit support, Wine became kind of useless on Macs since a lot of Windows software (especially older games) is x86 only. The announced move to ARM further decreases chances of Proton ever officially supporting macOS, as emulating x64 would be way to costly to play modern video games.