The fixed-function hardware that Alyssa assumed existed (vertex attribute fetch, special uniform buffer hardware) doesn't exist on many GPUs outside of mobile.

The fixed-function hardware that Alyssa assumed existed (vertex attribute fetch, special uniform buffer hardware) doesn't exist on many GPUs outside of mobile. In fact, Vulkan was designed to be a closer match for these GPUs, by making many of the same tradeoffs that Metal did. If they wanted to sabotage Vulkan, choosing the same tradeoffs as it and following the same path as most other GPU vendors doesn't seem like a very effective way to do it.