On the contrary, I would say this is the main thing Vulkan got wrong and the main reason whe the API is so bad. Desktop and mobile are way too different for a uniform rendering API. They should be two different flavours with a common denominator. OpenGL and OpenGL ES were much better in that regard.

It is not unified, when the first thing an application has to do is to find out if their set of extension spaghetti is available on the device.

Mobile is getting RT, fyi. Apple already has it (for a few generations, at least), I think Qualcomm does as well (I'm less familiar with their stuff, because they've been behind the game forever, however the last I've read, their latest stuff has it), and things are rapidly improving.

Vulkan is the actual barrier. On Windows, DirectX does an average job at supporting it. Microsoft doesn't really innovate these days, so NVIDIA largely drives the market, and sometimes AMD pitches in.

> One of the things Vulkan did which would be a shame to lose is it unified desktop and mobile GPU APIs.

In hindsight it really would have been better to have a separate VulkanES which is specialized for mobile GPUs.

Eh, I think the jury is still out on whether unifying desktop and mobile graphics APIs is really worth it. In practice Vulkan written to take full advantage of desktop GPUs is wildly incompatible with most mobile GPUs, so there's fragmentation between them regardless.