Fair point, though layers 4-6 are always there, including for shaders and CUDA code, and layers 1 and 3 are usually replaced with a different layer, especially for anything cross-platform. So this Rust project might be adding a layer of abstraction, but probably only one-ish.

I work on layers 4-6 and I can confirm there’s a lot of hidden complexity in there. I’d say there are more than 3 layers there too. :P