That's something of a sweeping generalization. Zink has managed to beat a native OpenGL driver in some particular benchmarks.
In many other benchmarks, it loses. That being said, it still manages decent performance, which is extremely impressive for a one man project using only the Vulkan interface. It wouldn't surprise me if it eventually becomes the default OpenGL driver in the open source driver stack (for HW capable enough to support a Vulkan driver, obviously).
Autodesk is using Vulkan for some products (including using MoltenVK for the Mac version).
As for using middleware, GPU's are vastly more capable and complicated today than 30y ago when OpenGL 1 appeared. In most cases it makes sense to use a higher level interface, specialized for the particular type of application you're writing, be it ANARI, a game engine, some scenegraph library, or whatever.
Regarding Metal, indeed those that leave OpenGL are more likely to move into middleware than forcing Vulkan upon themselves.
Hence why Khronos started ANARI, as most visualisation products and CAD/CAM people couldn't care less that Vulkan on its present state exists.