If your main concernin life is not getting hurt then I think you can probably go well into your 70s pain free before old age takes it's toll. But if you want to do things in life, challenge yourself, take yourself to and beyond your limits, experience the high and exhilaration that gives some zest to life then of course there are going to be some risks and a price to pay. It's the old lion and sheep analogy. Depends on how a person is born. What makes one content to sit and lounge, avoid any discomfort or chance of pain, and always remain physically comfortable as much as possible. Then there are those that want to lay a 800 lb bar and squat down for as many reps as they can until they are on the verge of having it collapse on them. I don't know what makes people so different and what motivates them. I don't why I've always had, since I was a little kid, this desire to be involved in contact sports. I just loved getting into fights when I was a kid and although I was never a punk I never let an opportunity to mix it up go by. Whether I won or got the crap beat out of me I've always gotten such a feeling of exhilaration while in the mix of fighting my heart out. It seems that the closer I felt to death the more alive I felt.
So you get people that destroy their bodies playing football, boxing, MMA, powerful lifting.... really all endeavors that require physical exertion, and then you have the rest of use that just watch them and with many living vicarious through them wishing the had the physical gifts, guts, desire and discipline to be there themselves.