With WebGPU/wgpu you don't get mesh shaders, ray tracing or shader subgroup/wave/warp operations. Its feature set is comparable to Vulkan 1.0, and Vulkan has progressed a lot since.
And WebGPU still requires all the RenderPass setup code which is a lot of boilerplate that Vulkan no longer requires.
Subgroups may seem like a minor feature, but they can unlock huge performance. I recently had a 10x perf boost with a very basic subgroup trick to let neighboring pixels collaborate on some expensive operations in fragment shaders. And there's another 5x in there waiting for me to implement some subgroup quad tricks.
And WebGPU still requires all the RenderPass setup code which is a lot of boilerplate that Vulkan no longer requires.