I think in the end it all depends on Android. Average Vulkan driver quality on Android doesn't seem to be great in the first place, getting uptodate Vulkan API support, and in high quality and high enough performance for a modernized WebGPU version to build on might be too much to ask of the Android ecosystem for the next one or two decades.

I try my best to push ML things into WebGPU and I think it has a future, but performance is not there yet. I have little experience with Vulkan except toy projects, but WebGPU and Vulkan seem very similar

WebGPU is kinda meh. It's when you need to do do something on browser that you can't with WebGL. GLES is the compatibility king and runs pretty much everywhere, if not natively then through a compatibility layer like ANGLE. I'm sad that WebGPU killed WebGL 3 which was supposed to add compute shaders. Maybe WebGPU would've been more interesting if it wasn't made to replace WebGL but instead be a non-compatibility API targetting modern rendering and actually supporting Spir-V.

WebGPU is kinda meh, a 2010s graphic programmers vision of a modern API. It follows Vulkan 1.0, and while Vulkan is finally getting rid of most of the mess like pipelines, WebGPU went all in. It's surprisingly cumbersome to bind stuff to shaders, and everything is static and has to be hashed&cached, which sucks for streaming/LOD systems. Nowadays you can easily pass arbitrary amounts of buffers and entire scene descriptions via GPU memory pointers to OpenGL, Vulkan, CUDA, etc. with BDA and change them dynamically each frame. But not in WebGPU which does not support BDA und is unlikely to support it anytime soon.

It's also disappointing that OpenGL 4.6, released in 2017, is a decade ahead of WebGPU.