There are optimization issues, but one thing to take into account, as mentioned by others, is that console GPUs are on such a lower level than any of the GPUs out there right now. You need much more power to run games at 1920x1080 or higher. The graphical settings are higher and there are so many additional options that stress the crap out of a GPU (such as PhysX or antialiasing). Take Battlefield 3 as an example. I have both the console and PC version and the difference is dramatic:
(1) The console version runs at 720p, which is a quarter of the resolution I play on PC (2560x1440). Such a low resolution cuts GPU demand down drastically. With all other settings equal, a console would not be able to even run Battlefield 3 on 2560x1440. There is a lack on vram and the horsepower isn't there. It would explode!!
(2) Antialiasing is absent in consoles and is an option for PC games. Enabling max antialiasing in Battlefield 3 (MSAA x4) will cut your performance down significantly. AA of any kind on a console would cause it to explode!!
(3) The console version looks worse than the lowest visual settings on PC. If a console GPU had to run Battlefield 3 on PC low settings, it would... explode!!
(4) Console BF3 runs at 30FPS. This is not a very ambitious target, but they have no choice. In order to get 60FPS on console, the graphics would have to look like Super Mario 64!!
(5) Outside of visuals, the console version can't even handle 64 players. In fact, it can only handle 24 players, which is about 37% of the PC player count!!
(6) !!
For those that think the "next gen" consoles will "even the playing field," you're naïvely mistaken. Those consoles will still run games at 720p, no antialiasing, 30FPS for most titles, and overall lower settings. You get what you pay for. If you pay $400 for a console and I pay $2,000 in just my GPUs, you can't expect to match me or even come close. If that were the case, then PC gaming wouldn't even exist. Why would anyone pay thousands of dollars for a PC to game on when a little $400 box made out of cardboard can outperform it?
Yes, PC games aren't optimized optimally, but they are still running games that are generations more demanding than the current and upcoming consoles. You know what's funny? My dual Titans actually have a better price per performance than the PS4 (no, don't tell me that the GPU in the PS4 is cheaper because the PS4 is a bundle of parts). My dual Titans are $2,000 and, according to Nvidia, 1 Titan is 3 times more powerful in terms of tflops than the PS4. I argue that if we were to benchmark the same games, the PS4 would be unable to perform any of them because the settings would be too much for the console to handle. Anyways, we'll stick to tflops for the sake of argument. So 2 Titans are 6 times as powerful as a PS4. Purchasing 6 PS4's would be $2,400 if the price is assumed to be $400 per PS4. Obviously you cannot throw 4 PS4s on your motherboard and run 6-way PS4 SLI, but you get my silly point.
While my argument may seem like overkill, I am outraged by how many simpletons think that the PS4 is the "ultimate gaming PC." Just ask the President of Epic Games