Even webgl don't give any gurentee about your code will run well on any devices though. It only gurentee that it will run, but it can have 10x performance difference on different platform depends on how you wrote the shaders.
As anyone used to Khronos APIs is aware, that is of little value without actual Conformance Tests Suites, and even then there are plently of forgotten guarantees when using consumer hardware with all the usual OEM quality practices.
Good then that even WebGL mostly doesn't run on Khronos APIs ;) (only on Linux, although I don't know whether ANGLE is now actually using a Vulkan backend on Linux - which of course is also a Khronos API though).
Both WebGL2 and WebGPU are probably the most 'watertight' specced and tested 3D API ever built, and especially WebGPU has gone to great lengths to eliminate UB present in native APIs (even at the cost of usability).
The Android OS and the entire Android ecosystem being a huge pile of excrement isn't really surprising though. But it's 'too big to ignore' unfortunately, at least for browser APIs.
I think the parent is implying there are 1001 soc out there with some form of embedded gpu that probably have issues actually implementing webgpu. Like those in millions of Chinese tablets. Are they likely targets? Probably not now but in 5 years? Mainstream desktop hardware? No problem.
