the consoles are jumping from 1.31 tf to 6tf and 1.81 to 4.6 tf , very massive jumps

1080 ia pretty much the standard on ps4

That is what the N3DS did. Try playing Hyrule warriors legends on both and tell me the 3DS isn't obsolete. Xenoblade chronicles 3D? Exclusive to it.

Yes, it makes no sense at all to me that they are trying to do 4K when they are still unable to do propper 1080p 60fps, not even among PC gamers 4k is that important, it needs too much extra power and you cannot see the difference without a very expensive TV.

You can have a 1 Teraflop GPU beat a 2 Teraflop GPU. You cannot use that as a way to gauge performance.

The performance jump should be less than what the Teraflop increase may imply as memory bandwidth, CPU speed, cache sizes, speed and latency and even things like the Render Output Pipelines and Texture Mapping Units are NOT seeing the same kinds of increases as the single precision floating point performance. (Tf/Teraflop/Tflop)
Rendering a game needs more than just ample amounts of single precision floating point performance.

With that said on the flip side, the performance increase should be more than what the overall specs sheet tells us due to efficiency optimizations that allow for more performance out of every pixel pipeline (AMD is saying 55%), boost to the geometry engines, bandwidth savings thanks to colour compression etc'.

Agree, it's an excessive leap for now. While for big TVs it makes perfectly sense to switch directly from 1080p to 4k, skipping 1440p altogether, as TVs are typically long-lived appliances, for gaming is quite preposterous to try 4k before even being able to max out 1080p and 1440p, as simply there isn't enough GPU power to run it with at least medium-high FX to justify it, except in ultra-high end PC configs that are neither for cost nor for power consumption viable for consoles or mainstream gaming PCs.

I expect 4k@highFX*highfps gaming to start becoming viable and VR to become mainstream with 9th gen, for what concerns HW value for money, but they'll need SW support too, it won't be automatic.