My point about the PS3 point is that even after all the cost savings from the drop in price of components and licensing fess with the aging of components, it still took more than half the console's lifetime to start turning a profit in the least bit. Even now a new PS3 is about $300.
It's not as if the AMD components in the PS4 are completely off the shelf either. They are for all intents and purposes a new CPU/GPU that is being used. Yes, based on existing core technology, but still not completely off the shelf, so there is some R&D that will need to be recouped. There is also the tech they've put into the new controller, which while nothing to get excited about is still a cost both in terms of R&D and in overall production.
Will the PS4 be less expensive than the PS3 at launch? I would hope that's a given. But they're not gonna be able to terribly undercut the rest of the console market either. It would help to have a better idea of the pricing for the next Xbox, but devoid of that the newest consoles we have to compare to are the refresh of the PS3, and the Wii U. The PS3 retails around $300, and the Wii U at $350. It's highly unlikely that they'll sell their console for less than $350 at launch, so $400 to $500 is the likely range. Is that going to equal to a financial loss? I expect there will be at least a little just because they are going to try to keep the price down on the console as much as possible.