Ah, I see what you mean. I was thinking more in terms of market-driven motives for adoption rather than technical facts. Unfortunately, Vulkan is currently still under development and under strict NDA so I can't disclose any of the inner workings at this moment in time (beyond what we have posted on the blog). However, when the spec is final and public, we will talk a lot about the technical implications in more detail, offering code snippets and tutorials so developers can understand how to use Vulkan.
When it comes to Vulkan development, it is a pretty much a joint effort. We (the GPU providers) design the graphics processors and write the drivers/compilers to support Khronos. Then the application developers (the middleware guys) adopt their engines and libraries for Vulkan too in cooperation with us and other members of Khronos. Finally, the high-level application developers (e.g. games developers) port their software too. In addition, third parties might also create Vulkan open source drivers and compilers for the GPUs so it's a combination of in-house and third-party work.