XC race bikes are not designed for comfort, but for going fast. More bike weight does not absolutely equal unsuitability for all-day riding. I use a 32-lb bike with a coil shock for all day riding. Body position, pedaling efficiency and ease of negotiating terrain up and down make a bike that’s easy to ride all day. It’s not 2012 anymore, trail bikes pedal well.
PS: Another guy trying to talk himself into being old? Give it up, you don’t have an excuse! : ) I’ll be 58 this year, plan on another banner year, replete with embarrassing many riders my junior. Old is an attitude, not a number.