Heat = poor reliability
Now wait, I can see the point of the price cuts and the price points sound reasonable, though I think killing the core unit right now would be a good idea, going forwards with the old premium and new elite at $299/$399 prices seems a better strategy to me personally.
That said, I am worried by the reasoning about reducing cost.
Moving to 65nm means less heat which means you need a smaller/cheaper cooler, and the mention of other reductions to the cost of manufacture.
First off, since the reliability issues are almost certainly heat related why would MS do anything to reduce the effectiveness of cooling in the system? With the newer 65nm chips, I'd have thought that the same or similar cooling system would provide a cooler system by more efficiently removing heat from the now cooler CPU/GPU combination. Moving to a smaller cooler seems like a very bad idea.
Since Microsoft got into the current mess with it's reliability by cutting corners and squeezing suppliers and manufacturers hard, why would they compound the earlier error by doing the same again?
Personally the move to 65nm seems like an opportunity to evaluate the design of the unit and make bloody well sure that the reliability is where it should be, never mind the cost. If MS doesn't regain some credibility regarding the reliability of the RROD 360, then no amount of price cutting will help them.