GM failed to perform an adequate hazard analysis. Faultiness is inherent in any vehicle driven for a number of years, and as we've seen a single fault can disable many safety-critical features like ABS or Power Steering.

The potential impacts of the failure modes of the key switch are quite severe, although in normal use the likelihood of any one is low. Because of the severity, some risk mitigation should have been in order regardless of whether the component "works fine" or not.