Yeah, it's more what the builder does with the material than what differences exist between materials. The reason CF is used now more than anything else is that, given the same build characteristics on any specific frame, CF is lighter. Plus CF can be formed to more interesting looking and aero shapes than other materials (shaped downtubes and topsubes, stays, cut away seatubes, etc.).

Me, I like to buy new bikes periodically just for the sake of having something new and excsting. I still have my 20 year old steel Waterford and 8 year old Ti though.

Also I wouldn't worry about the life of any material. They all will last longer than you do, assuming to take reasonable care.