They've come full circle:
1. AMD announces Mantle, a low level graphics API which may give consoles an edge over the PC.
2. Microsoft panics and announces DirectX 12, aiming for pretty much the same thing.
3. Khronos Group panics and announces OpenGL Vulcan, aiming for pretty much the same thing.
4. AMD announces there'll be no public SDK of Mantle, use OpenGL/DirectX.
So in the end we'll probably have feature parity again. How important it is remains to be seen, outside of drawcall benchmarks it's unclear how much real world difference it makes, what is certain is that it exposes a lot more of the complexity to the developer. That of course gives you more room to optimize, but it remains to be seen how many will be able to take advantage of it.
On the bright side, it might actually mean there's less code that needs to be written and that open source might catch up a bit, it says it'll run on top of all platforms that support OpenGL ES 3.1 which might become a much bigger goal than OpenGL 4.x.