So you are saying the RROD isn't fruit of rushing, but pure incompetence?
It took nearly a year before these reports started actually becoming a real thing, and even then it was unclear how widespread the problem actually was. MS didn't know what the problem was for a good few months.
Hindsight is 50/50 but they would have required a whole year of extra testing to test for something they would not have even been anticipating in the first place.
They thought they had a readily functioning console from the tests they had done and thought it was ok to launch. Its not about rushing, or incompetence, just bad luck.