Im in my mid 30s and I see your point for curiosity. I can only speak for myself, so the reason is ignorance and machismo. When younger you want fast, sexy and you never go anywhere far. Just ride with your boys around and do the occasional track day. Talk about horsepower and tt. Then you come out of the shell and realize there is a world to explore. But not to explore fast bc you will miss the journey. That's when a GS or KTM or KLR or whatever starts making sense. Now you may be more established and can take time off ( not just weekends) to go somewhere. Don't get me wrong, you can still have a sexy MV Agusta to do track days too, but your horizons -or borders- are now vanished and instead of bar hopping Sat night you may now turn to a lake trip in some distant mountain. Just my opinion
Btw I just got my GSA and I did notice what you are speaking off when I picked it up. You know something, the guys there were very informative and helpful and clearly knew their stuff . After 20 yrs of riding sports bikes I've learned the pleasure of riding without pressure.