The rather-low percentage hardware faults limiting availability may not be just because of rarity but more because hardware has a rather small set of "noise" fa

The rather-low percentage hardware faults limiting availability may not be just because of rarity but more because hardware has a rather small set of "noise" failure modes, which are easily handled by redundancy, while programmer/operator error has many more interesting failure modes exposed, and is rather harder to make redundant (contained engine failures are more common than CFIT, but the former won't bring a plane down crashing).