You're probably right about this. In the short to medium term, I expect that the Rust and C++ sub-ecosystems will be making different sets of choices. I don't know of any major C++ game or game-adjacent project adopting, say, Dawn for their RHI (render hardware interface) to buy into WebGPU. In the longer term, I expect the ecosystems to start blending together more, especially as C++/Rust interop improves (it's pretty janky now).