Less than 2 weeks isn't way before a release. They may have had prototypes out and testing for months already, as they will have for the 390x and 980Ti.
Don't think you get my point, yes, only two weeks before Titan X was released, but months ahead of the 390X and 980Ti release. If those charts are to be given any credibility, whoever created them most have had access to prototype hardware for the two cards I mention, way before anyone outside AMD or Nvidia has (and probably using drivers that wont mirror the real performance of said cards on release)
So, taking that into consideration, how do those charts compare to the real performance of Titan X now that the card has been out for over a week?
I see you're willing to give those charts a fair amount of credibility, and to be honest with you as an actual owner of a Titan X card, I think you give them more credibility than they actually deserve, if you're actually trying to use them to predict the performance of two cards that are probably months ahead of their actual release to the public.
I hope you can see the point I'm trying to make now.