No, don't stop using the classic steel bike. The reality is we're not as young as we used to be, and we can't do what we used to be able to do. The biggest adjustment for me was coming to the realization that I NOW have limits to my endurance and capabilities. It's a life-changing realization. Really is.
I know there are dudes my age and older that can outride some of the young boys. I'm happy for them. But I'm not them. It causes me too much discomfort to try to do what I used to do, so now I just do enough to stay fit and enjoy myself.
Case in point, this summer was unusually hot all season. Record-setting hot. Instead of trying to keep up to my normal level I just cut back. It was just too uncomfortable for me to ride in that heat. I'm still in decent shape overall, GREAT shape for my age group. I'll make up for it next season . . . F' it!! The idea is to enjoy life, not keep trying to be something that's unobtainable. One of the hardest things there is, is to come to the realization that your youth and your athletic capabilities are gone . . . for good.
Now days HEALTH is most important. Athletic accomplishments fall back down the list.