There are a lot of legends in their late 30s and early 40s, and then you even have extremes like Fuse and Mad Maggie, which are 55 and 56, respectively. In the real world, you would never see someone in their mid-40s, much less 50s near the battlefield. Age even if you're taking care of your body fucks you up and degenerate your physical capacity over time not to mention passive injuries like arthritis, back problems, loss of eyesight and hearing that occurs natrually over time. Then, if you aren't taking care of your body or doing stressful physical activities like fighting and getting into gunfights, that would accelerate these status effects. The fact that these older legends can compete with the younger ones hold their own and so much as not even complain once about their back or something implys that the medical technology afforded to people does a really good job at preventing age related injuries and fixing them if there are signs of it hell octance had the opportunity to regenerate his legs when he blew them off orginally he just decided not to. I just thought that was cool. That's definitely why blisk looks like he could still fuck someone up despite being an old man