The main reason the 8th gen doesn't seem like such a huge leap is the law of diminishing returns.
RAM and such may increase drastically, but as graphics become more complex, the differences become less, until you need 10x the power just to look x2 as good.
Then there's the lack of a major change in the way graphics are done this time around; the 5th gen leap saw the upgrade from 2D sprites to 3D polygons, the 6th gen saw the leap from crude 3D shapes to more complex ones, the 7th gen saw the upgrade from SD to HD, and the 8th gen... well, it's simply more of the same, just with more detail. There's no paradigm shift in graphics this time. (With the exception of Wii to Wii U, which benefits from SD to HD and fixed function shaders to programmable ones)
This is why, graphically at least, the 8th gen upgrade is less noticeable and impressive than previous generational upgrades, at least with PS4 and Xbone. It's still a noticeable upgrade, but if you were expecting a PS2-to-PS3 shift, I can see why you'd be underwhelmed.
