For me, I'd frame NASA's approach to software quality as a core value of the organization. The problem is that determining where a mission critical level of attention to detail is not necessary requires a mission critical approach because failure there means failure to develop mission critical code to support a mission critical function.

So the process of determining what does and does not require mission critical rigor has to be handled with mission critical rigor. Adding such a process is just one more point of failure. It requires the same attention as just writing the code "right" but is more subject to political maneuvering and other unproductive mental overhead and subjectivity.