The loss leading model has been succesful numerous times.
The loss leader model has also failed numerous times with companies lumbered with ever growing losses that killed the platform or even the company.
Wii is the only counter example, which IMO will be a very hard act to follow.
Pretty sure the NES, SNES, Gameboy, Gameboy Advance, DS, DSi, N64, GC and 3DS will all have launched at prices above or close to the manufacturing costs (no $150 ~ $300 losses that's for sure).
Consider this: A loss leading box with a BOM of $300 sold for $200 vs a box with a BOM of $200 sold for $200, which would sell the most ?
If the Saturn, Xbox or PS3 are the $300 console then I'll go with the $200 console.
You need to consider all the revenue streams when you talk about break-even. A loss on the hardware can be sustained as long as they have revenue form every software, media or service sold on the platform.
You also need to consider that not every revenue stream will grow (or grow proportionally) as a result of you losing more on the hardware. There's a point where growing hardware losses (or narrowing hardware profit margins) won't result in profits growing by a greater amount.
As for silicon cost reductions, even if the new, cutting edge, nodes won't see immidiate cost reductions, the older will. The bulk of silicon production costs are capital costs, as the equipment is amortized production costs are reduced.
But will that be enough to allow you to drop your BOM by 70% in 6 years? And in the market you will face in 6 years (or whenever) will whatever saving you can get be enough?
Will a maturing older process deliver the same cost savings as moving to newer nodes used to? It's not just cost per transistor, but the knock on costs like cooling, power supply, case, shipping and a sales boost from improved aesthetics of the slim model. Xbox 360 sales saw a sustained increase once the 360S was released - and so they should have because the 360S is a much nicer entertainment box than the big, noisy (very noisy) and unreliable older Xboxes (which were kind of shitty).
Once the core gamer market is hooked you need to be able to attract everyone else. The old style PS3 and Xbox were rubbish for that.