The reason people seem to think some slides make up for that is this question:
Number of to-be-shipped games running the API?
- Mantle: ??? Dunno, depends on how many devs decide they like it.
- DX12: Lots, because it's DX.
Can you disclose the marketshare of DX11 games vs DX9 right now? That is, after almost 5 years of DX11 release.
Also, let me just leave this here, so you can draw conclusions about the time required to make an API, according to wikipedia:
On the "DirectX 11" article:
"Direct3D 11 was released as part of Windows 7.
It was presented at Gamefest 2008 on July 22, 2008 and demonstrated at the Nvision 08 technical conference on August 26, 2008.
[...]
First seen in the Release Candidate version, Windows 7 integrates the first released Direct3D 11 support. The Platform Update for Windows Vista includes full-featured Direct3D 11 runtime and DXGI 1.1 update, as well as other related components from Windows 7 like WARP, Direct2D, DirectWrite, and WIC."
On "Windows 7" article:
"
The release candidate, build 7100, became available for MSDN and TechNet subscribers and Connect Program participants on April 30, 2009. On May 5, 2009 it became available to the general public, although it had also been leaked onto the Internet via BitTorrent"
Roughly 9 months from announcement to first appearance to the public. Seems like a prudent window of time before announcing a new API and actually releasing it.
Now with DX12 we have..... 1,5-2 years at best, between announcement and supposed launch. Lets sustract 4 months because we might be actually be able to preview it on a preview candidate of the new OS that will be shipping with it... Still nowhere close to the times handled behind the DX11 launch.
So why MS announces this new API 2 years in advance, going against what they did with the API that preceded it? Suddenly API developing costs in time became much higher, or is it that they made this presentation to do damage control of the pressure felt by the launch of that puny little API called Mantle?