"MS: Apple is not comfortable working under Khronos IP framework, because of dispute between Apple Legal & Khronos which is private. Can’t talk about the substance of this dispute. Can’t make any statement for Apple to agree to Khronos IP framework. So we’re discussing, what if we don’t fork? We can’t say whether we’re (Apple) happy with that.
NT: nobody is forced to come into Khronos’ IP framework."
1. It's so low level that generating HLSL and MSL from it is more painful than it could be. For example, it represents branching in the form of a Control Flow Graph (which is typical for an IR). This is lower level than either a source language people would use (e.g. GLSL), or the destination backend language we need to produce (e.g. HLSL or MSL). This is unnecessary complexity for translation.
2. It has a lot of instructions, covering wide range of hardware (somewhat similar to Vulkan). In contrast, for WebGPU it would make sense to have fewer instructions for the ease of securing it and translating to other representations.
3. Friction in the features we need, vs features Khronos needs.
There is also a situation where there is no single well specified and tested textual shading language. HLSL doesn't have a spec. MSL has documentation, but not enough for a spec, and it's not portable. GLSL kinda has a few specs, but realistically it's just specified by the implementation of glslValidator.
There’s a lot of opinions from people outside the working group for WGSL as to why it exists.
I think most of the PR damage right now comes from those people not having enough context and thus framing it in a negative light.
A blog post with more context and information would probably help imho
While moving from OpenGL to Metal was a significant technical upgrade for them, moving all their ecosystem from Metal to Vulkan is just a lot of work for very little benefit.
But yeah, sure, maybe they are just sticking with Metal to mess around with people.