Re: I would guess MS is to blame
May I point out that MS had the same inability to read a thermal spec issue with the Xbox 360 and the RRoD? Which is why they had to go to IBM's more expensive SOI process to move the processor temperature down. (Not that it was totally MS's fault, but they should have done a better transition to lead-less solder like most other companies did.)
I would suggest there may be a lack of attention to thermal engineering in the MS hardware department and too-slavish deference to design engineering. A failure in one flagship product is understandable, but not learning from it speaks volumes about the culture in MS's hardware division.