That's not the issue, the issue is how do I put on 200 mm2 90 nm something that can approach for real 200 gigaflop/s (or integer ops, for what is worth) ?I don't think I agree with that completely... I look at it as more of an engineering time & budget problem. A Core 2 Solo wouldn't be very big if it existed, but IBM never created a CPU core with an IPC comparable to that, and if you look at the direction they're taking with the Power6, possibly never will.
IPC on SPU is very good (approaching 2..), on optimized code, the key factos here is: this stuff is not going to change for 5 or more years, devs will optmize the hell out of it.
We could have got a blazingly fast intel CPU with 2 cores, or even 4 and then we would have been able to code for it without going crazy and we would be all happy...and we will be outperformed by next year pc.
Try to guess how many core 2 solo cores you need to implement a modern game post processing rendering pipeline (and how much bandwidth you need as well from your caches when the other cores are supposedly trying to run some other code at more than an instruction per minute rate ) and how many SPUs you need to do the same job.
I'm sure a lot of devs would answer something like "but we don't do post processing effects on the CPU, or we don't tessellate geometry on the CPU, or we don't trim every single not visible primitive at subpixel level on the CPU, or we don't implement sw rasterizers to compute dynamically occluded geometry on the CPU, or we don't generate IBL data or do ambient occlusion at run time with the CPU, etc etc..and for sure we don't do all these things at the same time cause we don't have the bandwidth and/or the computational resources..." even in a closed system enviroment.
In the end it's all matter of tradeoffs, if you sell a console and you need to do it for several years to make a profit and you think that other platforms that will make your platform look outdated will decrease your profits you have to do something about it, this is a game that has to be played for 5,6 or even more years, and you need to be competitive for a long long time.
A lot of assumptions here, many of them are probably wrong (see Wii..), so yeah..I should probably shut up (linking complete, back to more productive )