If I recall correctly, I've seen examples of the shuttle code printed out in a large volume (or volumes), where the code is documented line by line. In a way it is a testament to the relative immutability of the code and maturity of the work. I find it to be highly impressive and also suffocating at the same time.

In my experience, a lack of software quality is frequently introduced as a result of hurried time lines and limited resource allocation for quality and reliability. In other words, it appears more of an organizational, project management, or business failure.