You keep posting this again and never seem to get it. (Sometimes, like now, its 2x other times its 2x + 2x, or two titans; at least make up your mind)
1. That assumes optimizations and such. ~2x is the final figure, This also comes later in the dev cycle.
If you look at console ports you can see the the xbox 360 / ps3 in a straight comparison with modern gpus is around a 630m. Ports such as skyrim, dishonoured, me3, are playable on those gpus at the same or slightly better settings than the console versions.
2. 1 Nvidia GFLOP != 1 AMD GFLOP. gtx 780 != 7970 ghz despite having a similar number of GFLOPS (boost). That should tell you right now that GFLOP arguments should really be taken with a grain of salt and should always be compared across architectures whenever possible (I don't know why you are always comparing to nvidia instead of amd when both consoles are GCN; comparing to AMD we get a a ~7970 (non ghz) level of graphics performance which is significantly less than a gtx 780).
3. We cannot compare current games to next gen games. Current games are build on the same base as consoles and dressed up for the pc. Scaling between visuals and the required power is anything but linear (often minimal difference between high and ultra despite fps tanking). Take bioshock infinite for instance, high res textures and fairly demanding but because its built on a console base you get things such as
(Bioshock infinite high settings- no dx 10/11 effects, everything else maxed)
Everything maxed
Basically no IQ gains for a near halving of fps. And look at that ugly planter of roses.
Hopefully next gen will fix this but until then games are basically putting lipstick on a pig. Costing tons of fps for almost no IQ gain. This is why comparisons should not be made between a pc game maxed out and a console game.
Here is a scene in which more can be seen
High
Ultra
(Basically no IQ difference, the trees in ultra are very slightly more detailed and for some reason the bell tower isn't as tall, contrast is very slightly better on ultra for the background). But is it worth the fps loss? No. In a game designed for better effects the fps cost of high vs ultra would be much less (maybe 4-5 fps vs the 17 fps it costs here).
I have no doubt that next gen consoles will have amazing graphics but please don't try and compare to maxed current gen games which are mostly glorified console ports.