Sure, but we already have the GL vs Vulkan environment. Is there actually a meaningful difference between Vulkan 1.0 and 1.1 that's not going to end up being an extension or feature bit? And, if we don't know of one yet, do we need to add this extra API switch yet?
I don't understand, are we adding an API switch? It seems that we're only adding a case to an API that already exists (and is the one that enables the SPIR-V writer to distinguish between OpenGL and Vulkan 1.0; now we also have Vulkan 1.1). My feeling is that since SPIR-V already has a concept of "environment" we should stick to that one instead of inventing our own, so that anybody already knowing SPIR-V finds it a familiar concept instead of having to learn something similar-but-not-completely-the-same which might be puzzling. Also, coming up with a different concept might mean that at some point the SPIR-V concept and ours diverge in some sense that requires us to change our API to something more unwieldy.