This isn't strictly true. Aluminum and steel certainly do corrode very differently, especially due to the protective properties of aluminum oxide layers, but it

This isn't strictly true. Aluminum and steel certainly do corrode very differently, especially due to the protective properties of aluminum oxide layers, but it's definitely much more complicated in terms of overall longevity. One of the main factors for this sort of the things is the mechanical fatigue that cars experience. Whereas steel and other ferrous alloys have something called a 'fatigue limit' [1], where for a given stress, they'll maintain integrity indefinitely (at least for practical purposes). Aluminum, on the other hand, will continue to experience an increased likelihood of failure under small and smaller cyclic loading. Estimating mechanical longevity from a small number of first principles concepts like materials is extremely difficult, and usually is only be conclusively determined through statistically relevant groups undergoing destructive testing. [1] https://en.wikipedia.org/wiki/Fatigue_limit https://en.wikipedia.org/wiki/Fatigue_limit