The better case is to use one of the inevitably many rendering libraries that will be developed for Vulkan that abstract away the implementation details in much

The better case is to use one of the inevitably many rendering libraries that will be developed for Vulkan that abstract away the implementation details in much the same way OpenGL did before. The problem with OpenGL was that it was the lowest level of access you got to the device - a high level giant API that hides the implementation behind it. Which made it a massive PITA to implement for hardware vendors, and slow to adapt to changes in the GPU landscape. It is very likely we will see an implementation of OpenGL that compiles to Vulkan in the same way we are seeing immediate development of VK -> Metal compilers and will probably see DX12 -> Vulkan as well. You just need an API wrapper and a shader translator that takes their respective shader formats and compiles them to SPIR-V rather than the original targets.