The issue is that you can't always argue price, because every console has an entirely different economic strategy.
Would a $300 PS3 sell better than a $300 X360? Absolutely! It has the brand name recognition, and good hardware like the Blu-Ray to make it a strong value buy.
But at the same time, Microsoft took the cheaper, less costly route of no Blu-Ray, and less expensive components (like Nintendo has) so their consoles could be far more competitive in the pricing wars.
What good is it to argue how well a $200 PS3 would do if it isn't going to come for years in the future? Right now, the PS3 is possibly going to break even at $400 soon, while the Xbox 360 is profitable at the $200 basic model. Do you understand how big of a difference that is concerning cost of manufacture?
It's something you have to look at...Value vs. Price. That's why certain consoles do the best - Wii has sold very well in the US due to price, and opinion that it's a great family console. PS2 sold well because it had all the games + DVD playback, and was affordable, and so on.
And I think when you get down to the lower prices, you have to look at ratios of cost vs. eachother. Right now, the X360's Arcade (in the US) is about $120 cheaper than the PS3 at $400, or 30% cheaper. If it was a $200 X360 vs. $300 PS3 (which I doubt will happen for very long), it's 33.3% cheaper. Not only this, you have to look at the % of people that can afford that price difference - The cheaper you get with your console, your going to find more people willing to pay $200, but not $300....Versus people paying $300, and willing to pay $400 for the "better" console.