Honestly, from an engineering perspective- they've probably corrected the overheating problems as much as possible (or as much as the accountants will let them)- but still put that in as a last ditch protection mode just in case. Current computers processors do that too- shut down when overheating or throttle their clock speeds back to prevent damage- but they're not supposed to ever have to. If I was on the engineering team redesigning the 360, I would have done the same thing- prepare for the worst, then go one step further to prevent the worst from happening. You can't guard against every single installation environment that a consumer might put your device in. Some retard might wrap it in a towel and then throw it in an entertainment center with no ventilation.