[chasontherobot]

#1 matters if you want to own and ride a bike for a few decades, which used to be a relatively common thing.

[midoridensha]

I've seen no evidence that aluminum bikes don't last a few decades. Frame failure is not a common failure mode in bicycles.

[wiredfool]

I've had two frames fail with fatigue cracks at ~ 10k miles or less. One steel (at the chainstay bridge weld) and one aluminum (at the seat tube/bottom bracket weld).