Market leaders tend to push proprietary stacks (because they can). While underdogs push open stacks (because they must). If the open standard is better it can win. This is how nvidia gained the upper hand over 3dfx by pushing opengl and directx alongside ATI. They surged ahead and glide died along with 3dfx.

Behold, history repeats itself.

I'm hoping that Vulcan will be that new competitive standard moving forward. I don't have much hope for open hardware and open drivers from market leaders (who are too concerned with losing their edge to competitors) but I would be happy with an open API that leads in performance across vendors.