CD Projekt would not gimp the pc build last i herd dual 780ti's could not even run the game at 30fps but that was 10 months ago
We can hope they wouldn't, but CDPR has to make this game for three platforms simultaneously instead of just one now.
As far as needing two 780ti's to get 30fps, no way. That would more or less suggest that the visuals between the PC and console versions would be significantly different. Also, probably less than 1% of the gaming PC base actually has such a ridiculous rig to start. I'd be shocked if the recommended settings require more than a single GTX 760 quite frankly (no game on the market requires SLI or CF support and we've only seen tech demos need that much graphical power).
This isn't the same jump we saw from The Witcher to The Witcher 2. CDPR even admitted that visually speaking, The Witcher 3 is primarily just increasing the polygon count. Otherwise, it's not really making any substantial pushes beyond what we already saw with The Witcher 2, which still looks pretty good on ultra settings for the PC to date.
I'm honestly not expecting any games in the foreseeable future to really push the boundaries in regards to system requirements. Perhaps Batman: Arkham Knight might raise the bar as that game looks incredible on it's highly-modified Unreal Engine 3. Honestly though, we'll probably have to wait until Crysis 4 or Battlefield 5 before we see something truly breathtaking.