Ha, ha, ha, ha, ha. Aluminum frame longivity again. What a farce! Certainly aluminum frames can fail, but the idea that every aluminum frame is a time bomb counting pedal strokes until it self destructs was conceived by a bunch of people who wasted too much time reading books. Time that would have been better spent riding their bicycles.
Go out on any group ride, the bigger the better. Look around at what kind of bicycles ordinary people are riding. Estimate the age of the bikes that you see. Now here's the important part: Trust what you see with your own eyes. It's good to learn technical stuff in school, but you have to see how that knowledge applies to the real world.
Personally, I've never had a bicycle frame that didn't last longer than I wanted it to.