Being a father of a 6 year old who has already had a minor concussion and a bruised nose, l kinda feel this one. Little kids do seem to roll with the punches better than adults, especially if you respond less dramatically. I assume a lot of that is due to being shorter and lighter weight though, leading to less forces overall, basically the square/cube law in reverse,
However, i do find a lot of folks who complain about how fragile they are do 0 cardio or weight training in order to strengthen themselves. My single most common recommendation is to do some kinda training for both, even if it's just once a week. I'd say it's probably the best investment you can make up to a certain upper limit time wise.
I'm sure there are some folks with old nagging sports injuries that bother them, for me that's my knees from 400+ pound squats, but in general I'd say I'm extremely resistant to day to day problems that affect most people besides minor to moderate muscle soreness/fatigue which mostly comes from the training itself. The only exception for me being my neck, especially from "sleeping wrong", which makes me think I should actually do some of the exercises that actually train your neck...
Again, I'm not knocking individual folks for their specific issues, but I feel like a lot of "normal" folks' problem is that they're just weak from years of being sedentary and a good general fix for that is just a bit of strength and cardio training.
To me that's a good thing because that means for most folks there is a fairly simple albeit not necessarily "easy" solution. I find problems I have the ability to directly fix are best.