I have had both Steel and Aluminum bikes. I like both and I plan on getting a CF bike next. But I am not into touring so my needs are different. I may even add a carbon fork to my Aluminum Road bike. They all have their advantages. Aluminum is lighter than steel for “the most part” so getting a lightweight bike in Aluminum is less expensive for the normally than steel. It also seems as if Aluminum is stiffer than steel and for climbing with a bike club flex seems to bleed off some power. Carbon Fiber is can be made light and can be designed to be stiff and light.
There seems to be a rule in cycling that the lighter the parts the more they cost. But as far as steel lasting longer I don’t know how relevant that is. The frame might be steel and parts like the handlebars, fork and seat tube might be steel. If they are then you are pushing more weight than most Aluminum bikes sold by your LBS. You can make a steel bike lighter by upgrading the parts just mentioned but if you ever upgrade the parts on your bike the shifters, derailleur, cassette and new chain will still cost more than a steel frame. So the only solution I can see is more than one bike. But then that assumes this question is real and not just an attempt to get the Aluminum verses steel debate going all over again.