You are forgetting one major factor. Not all PC's can do it so developers cannot depend on it when developing a game on pc(for example Fifa 14 for PC is going to use the ''old'' engine because otherwise it would not be compatible with alot of pc's). Also with the PS4 both cpu and gpu are on the same chip, using the same memory pool(therefore sharing tasks much faster). A standard pc setup with an additional graphics card is not comparable.

Yikes, that's pretty horrible.

They didn't do it in parallel, that was the whole point of Cerny making the changes to the GPU.  Time sharing != parallel.

And especially missing a PSU.

why would anyone want to build a ps3 type PC for $260

what about an xbone can i build an xbone type PC for $499 or a Wiiu type PC for $299

Optimization is the new Blast Processing.

Eh. Works both ways. The origional Crysis ran with better graphics on PC hardware that was similar to the consoles, but the console version was clearly inferior.

Games like Battlefield 3, by default have better graphics than consoles, so you can't even compare them.

Games like GTA IV were so badly ported, it was crap from a performance/image quality perspective. - The PS3 ain't immune to this either, case in point: Skyrim.

Now an equivalent specced PC will cost more than the console counterpart, but if you buy 100 games and they are usually $10-$20 cheaper on PC, you are saving $1,000 - $2,000 right there, even cheaper when you have a Steam sale making that saving massively larger.

Then you need to add in the additional costs of all the accessories and online multiplayer and the cost savings fall heavily in favor of the PC over time.

There is no reason to buy a BluRay drive for the PC if you were building it. Buy the cheapest possible DVD drive and install your OS and never use it again.

Why would you put 8GB of GDDR5 shared memory in a PC? That wouldn't even make sense. Building an exact replica of a PS4 would be stupid. Building something that runs the same level of graphics would be a completely different setup.

I'm sorry, you're giving opinion not fact, I've given you some perfectly good real-world examples of why your statement just generally isn't true.

Besides, do you really think developers really optimise games for every single graphics card on the market?
No, they don't. - Not only would it be financially difficult, but it would add a massive amount of time overhead to the development schedule.
Enter API's or Application programmable Interface, so that developers don't have to get down to the bare metal.
AMD, nVidia and Intel then build their hardware to support that API's features, no longer do Developers have to build games around any particular set of hardware nuances, they can assume it's all going to be the same. (This is why Microsoft has had influence over the PS3 and PS4's GPU tech as nVidia and AMD build their GPU's to meet Microsoft Direct X specification.)

nVidia, Intel and AMD then get to work on their compilers and memory management systems etc' in the Drivers that interface with the API's to extract as much performance as possible.
Compilers these days are actually rather good, AMD used them heavily to extract as much performance from their respective VLIW5 and VLIW4 architectures on the fly.

Besides, most developers license game engines from 3rd parties, like this generations heavily abused Unreal Engine, which is actually heavily optimised on the PC, it will easily run on console-specced PC's with relative ease, provided developers don't add longer more complex shaders, improved shadows, improved lighting, improved textures, improved geometry and models and the user keeps it running at 720P or lower with 2-4x AA so the comparison is fair.