Plenty of rumours suggested 2560+ shaders clocked at much higher core clocks, GDDR5X, along with anticipated architectural improvements. This would have put 480X easily at Fury X performance, or even slightly higher. Even without GDDR5X such a GPU should be better than R9 390 performance.
Think R9 390 at 1400+ core clock with GDDR5X and the extra architectural improvements to improve efficiency etc. The difference at most resolutions between R9 390 and Fury X is on average ~35%.
Hell even a R9 390 (2560 shaders) direct die shrink at 1400+ core clock would come close to Fury X. It really wasn't within the realms of fantasy to assume such a card was (or even is) possible.
If P10 with 2306 shaders, 1266 core clock only manages to match R9 390, which has 2560 shaders and 1000MHz core clock then AMD have ****ed up. Even with 256 instead of 512 bit memory bus such a card should be a distinct improvement on R9 390.
So please don't try the "maybe you all got over hyped for Polaris".