Wgpu-rs is also going down the rabbit hole of re-inventing the world: in addition to implementing WebGPU and targeting all the GPU APIs that are available, we are also trying to do all the shader translation ourselves now (project Naga). I hope to not be burned by this.

Pathfinder future is unclear. It's not ready to be integrated into WebRender yet, and Patrick no longer works for Mozilla. I see no activity on their projects. Would appreciate if they show up here and clarity.