You didn't listen to the interview did you? It was clearly stated that they were planning on giving Mantle to Khronos. And that's exactly what happened. Vulka IS pretty much Mantle 2.0. That action speaks for itself. It's also in the name... Mantle as in earth's mantle, and Vulkan refers to volcanoes. They gave it to Khronos because nVidia didn't want to support it, and they knew it would die without them. And if you listen to the nVidia interview, first they say Mantle has no benefits because lower level APIs are not that great, and then a few minutes later they praise DX12. That alone tells me enough about nVidia. They have been known to lie in your face. GTX 970 is the most popular example. And yet people still lick their balls.
As for Intel vs Mantle, read this:
In a separate email, the Intel spokesman said that it had been working with the Khronos Group and with Microsoft to ensure that future APIs target "a wide range of graphics hardware".
http://www.pcworld.com/article/2365909/intel-approached-amd-about-access-to-mantle.html
What does that tell you?
As for Far Cry 4... This says enough:
http://www.hardocp.com/article/2015/06/24/amd_radeon_r9_fury_x_video_card_review/7#.VZAN1xtViko
4K is a bad example because the Fury X is pretty much faster than the 980 Ti 90% of the time at 4K. And the reason for that is simple. The higher the resolution, the more the graphics card is put under load. Limits by CPUs and drivers become less.
Again, when DX12 rolls around, I can give you a 90% guarantee, that AMD cards will suddenly get a boost in performance while nVidia's won't as much. Their raw power will finally be used like it's supposed to.
As for your tech report link... They say this:
"We've seen lots of similar scenarios in the past where Nvidia took the initiative and reaped the benefits. Perhaps this is karmic payback." Says enough. And even then, it's not as bad as the tessellation under a city. Dirt Showdown was the first game to use Global Illumination. And it actually had visual benefits. Tessellation on invisible water under a city has no visual benefits. And even even then, nVidia has access to global illumination source code. It's only logical that something that has been used for the first time in a game will have bad performance on the other group. But when something is repeatedly used and it STILL affects the competitor's performance more negatively than it should, it's a sign of maliciousness. It's good that AMD drivers have so many override settings. If it weren't for that, performance in any GameWorks game would be abysmal since nVidia ties it to other settings within the game, without being able to change the nVidia specific settings alone. Also, AMD will never get access to HairWorks source code, while nVidia does have access to TressFX source code.