That would be a problem indeed if Metal wouldn't be a much better designed API than Vulkan. As it stands, Vulkan would do good to 'steal' a few ideas from Metal to make the Vulkan API more convenient to use without sacrificing too much performance.
The problem is, for that to happen Vulkan must be convenient and enjoyable enough to use that people are willing to put their free time into such middleware layers, otherwise it mostly won't happen (unless Valve is willing to sponsor the development - because outside of Valve's effort to make Windows games run on Linux via layering D3D on top of Vulkan, Vulkan is actually quite irrelevant).
At least for webgpu, you cant wrap around some of the nonse. Like bindigs. They are an inherently bad concept and the way to go would be bindless, but you cant make a wraper that makes an API that revolves around binding into a bindless API. And there are other things like that, and I'm sure there are plenty between Vulkan and Metal.
