Microsoft testing structure goes like this:
Release a brand new product with little or no testing
people buy it anyways
people tell you the flaws and good things
eliminate flaws and expound on the successes in the the next version
Release new version
roll in the money as you have not only created an excellent system, but you practically got paid for free product testing.
and if you think this doesn't apply to the xbox. think back to when the xbox 360 was first released and how terrible the tech was. (and dont get me started on the red rings of death)