I'm not disagreeing with you, just pointing out the irony. There was a time when GLIDE and OpenGL ruled--3dfx vs. nVidia, respectively (and D3d had not yet been born or else was too immature to matter.) Most people railed against this and heralded D3d as the API that all IHVs could participate in, compete in, and support. Would you want to go back to the former standard? I'm not saying I wouldn't...and not saying I would, either...
Yes, and if D3d development had ended with DX7 then some other API would likely have usurped it years ago. But it didn't; D3d kept on progressing because of Microsoft's support and influence. There's no reason Mantle cannot continue to develop just as D3d has done for all of these years.
Here's the thing: is Microsoft getting tired of managing D3d? I think there are signs that Microsoft is getting tired of doing a lot of things it has traditionally done (which I think is a mistake, but that's another story), and D3d might just be one of those things the company would be more than happy to hand off to AMD--I say AMD because nVidia's relationship with Microsoft has been rocky for many a year and I doubt it will ever improve. It seems like most of the D3d advances have come from ATi/AMD, anyway, over the last decade. (nVidia is still deep in its proprietary cups with things like PhysX, CUDA, etc.)
However, even though nVidia stated publicly years ago that it did not officially approve of "the direction" for 3d gaming that Microsoft was charting with D3d--after it put nV3x behind it, nVidia has never had any trouble fully supporting D3d in the years since--inspired by AMD or not, as the case may be. I think that more than answers the question as to whether nVidia could adapt to Mantle as surely as it has adapted to D3d.
So, what if there's an under-the-table understanding between AMD and Microsoft that AMD will slowly take charge of the API side of the business over the next few years? After all, AMD is in the ideal spot to do so, manufacturing both consoles as it does. Microsoft has two out of three positions cornered, the PC, and the xBone vs. the PS4, so even if the PS4 does well it does not mean Microsoft won't do better. Ah...speculation at this point is premature!
But if you are a developer and you want to support xBone, PS4, and the PC through a single API, and at a low level nearer the hardware, what else is there except Mantle at the moment? That said, is Mantle any good? As others have asked, how are the developer tools and so on? I think that the idea of Mantle for AMD has legs--but whether the actual Mantle code does is a horse of a different color, certainly.
