It has something to do with how consumers want their products physically smaller. So that means everything has to be smaller, the case, PCB, etc. So what happens when something gets smaller? Something has to give, and with the 360, that time was stability.
Other times, rushed production results in lousy performance overall, and probably shortened testing.
And just to note, all the computer parts made back then were weaker compared to modern day chips, so failures caused to overheating will me much more common with products made today compared to products of yesteryear.