DOn't forget that AMD and Nvidia are bigger and offering techical help and engineers to help. AMD sent guys in which turned, I forget precisely which version of Stalker from a crashing pieces of crap into a stable and updated to DX11 game(which I still didn't like but that is personal taste, nothing more).
DX needs to die off, that is why I said that, I didn't say high level API's need to.
openGL is there, it IS updated, if DX died off openGL would get a lot more support from AMD/Nvidia and get moved forward more.
DX does indeed need to die, it "won" the API war way back when because MS ran the table for PC's. There was no Android, there wasn't even much in the way of Apple, there was no SteamOS. DX was the defacto standard because MS pushed it, owned it and owned the market. MS is losing marketshare hand over fist, android will push up into pc's/laptops in the future, linux will be a bigger deal, Steam OS has a decent chance. The ONLY option for gaming to become universally compatible is for a completely open standard high level API to take over from DX. Thus DX needs to die.
We want low level API's so the guys with money, or the guys who want to make something new and awesome and find low level access is required HAVE THAT OPTION. Then a ultra compatible, industry standard, will run on any OS openGL API for everyone else.
I don't particularly think Mantle will kill off DX itself, it will just be one of the reasons. AMD have started Mantle now because this was the time to move against MS/DX/gaming monopoly on PC's.