Nobody needs all of Vulkan, but everyone needs quite a bit of it. Buffer allocation? Command encoding? Scheduling? Synchronization? Abstracting GPU architecture differences (and GPUs vary a lot)? Render pipeline fixed-function stages like primitive assembly, tiling, and blending? You're signing up to implement all of that - good luck!
In this view, your idea is the assertion, "I could do a better job at all that stuff than the driver developers." Maybe so! They're only human. Drivers do have bugs. But you're only human too.
Also, the onus is actually on the GPU manufacturers (not game engine devs) to simplify the programmability of the GPUs to the level we have for CPUs (we also do not write microcode, however, the programmability is much much simpler with access to good compiler toolchains). This will massively help non game engine developers who need GPUs for other kinds of compute.
1. It's a game studio not a project (CEO here :))
2. It's very much still alive and well today, not 'cancelled'
3. We never even used WebGPU in Rust, this was before WebGPU was really a thing.
It is true that we looked elsewhere for a better language for us with different tradeoffs, and have since fully embraced Zig. It's also true that we were big proponents of WebGPU earlier on, and have in recent years abandoned WebGPU in favor of something which is better for graphics outside the browser (that's its own worthwhile story)..
But we've never played /any/ role in the Rust gamedev ecosystem, really.