That's true for CPUs as well. What happened with Intel CPUs before 22nm? The biggest hyped process became the lowest gain in years.
Remember Fury's HBM? We've seen that it was a necessity just to be able to compete with Nvidia, rather than jump forward.
I think the companies are becoming better and better at hyping technologies. I don't think many of us expected both Nvidia and AMD were planning a staggered launch.
Isn't it clear by now that 2.5x perf/watt gain is over Tonga? And its 2x compared to current generation? We don't even know that will apply uniformly to all Polaris products. Also don't forget 14nm only applies to the computing part of the video card. It certainly doesn't apply to memory, and even I/Os on the chip gain far less. That's marketing for ya. I can't believe that top Polaris will be faster if at all than Fury X if they justified on releasing $1599 Radeon Pro Duo. A 20-25% gain would be too close to one that would cost 3-4x and get 80% gain situationally. Unless they make not-the-smartest decision.
$1599 Radeon Pro Duo
$400 Polaris 10
If Polaris 10 performs better than Fury X, what goes in between $1599 and $400?
Comparing this to the CPU space is not apples to apples. CPU performance relies on single threaded improvements, which at this point can really only be attained with higher clock speeds.
Fury X didn't need HBM to compete, hell, Hawaii is in the GM200 range in DX12 without even using their color compression tech with regular DDR5. If anything, AMD is the one whos had the better hardware this entire time. On top of that, they have not even done a major overhaul yet like Nvidia did with Maxwell.
Also, we don't know what AMD is cooking up. They may go the NVidia route with Polaris, and strip a lot of the compute abilities out of it, which would still necessitate a need for the Pro Duo.
The fact of the matter is that history and rumored specs have this thing in Fury X range, and the only thing you have really to counter it is
"nuh uh". We are on a new process node. look at every new GPU generation ever released on a new process node, and you'll realize that pegging Polaris 10 in Fury X performance range is actually being conservative.