the hardware in the consoles is optimized for gaming and the games are optimized for the hardware...
It's more the case that the PS in particular has memory unification, and a low level API in GNM, but the latter is software, not hardware. The Xone is getting a low level API via Dx12 come end of this year, but PC will have it by then too. PC is also getting memory unification via new Nvidia GPU architecture (Pascal's NVLink) and CUDA 6 (Maxwell's virtual memory unification).
As far as games being optimized for the systems though, that is entirely the fact that consoles having fixed, specific hardware are are much less likely to have compatibility problems, and devs put more effort into writing for them because they still garner 80% of the AAA title profits.
While PC IS suffering a bit from tech advances needed, many of the tech problems in today's PC games has little to do with that and more to do with the devs farming out the PC ports to their lowest skilled, lowest paid teams that are asked to do rush jobs.
When you look at the few dev teams that give PC it's proper devotion though, like CD Project Red, it's easy to see that 99% of the problem with PC game development is lack of interest from developers, not problems with the platform itself. Most devs have sold out the the console cash cow.
Even WITH all that, it's easy to see given a proper beast gaming PC, that you still find the best quality graphics are on PC. Even in multi plat titles that are technically flawed on PC, you can still find lots of 1080p 60 FPS YouTube videos captured from PC that look FAR better than the ones captured on console.