I agree that a bad fall is likely to be the most serious and incapacitating thing that could happen to a person in the woods--even more so at home. It is even conceivable that you could also get a serious puncture wound at the same time. So first, you are extra careful when you go walking in the woods, the same way you are when you wash the good china that only gets used at Christmas.
But no matter how careful you are, if you keep at it, sooner or later things happen. A twisted ankle, chipped heel bone, chipped china, crazed teapot and so on. I've never been immobilized, however, but there's a first time for everything. Even though I go to places that are relatively busy, I couldn't count on anyone happening by to lend a hand or even being close enough to hear a signal. Even then a signal would have to be recognized as a signal and not a random noise from a bunch of kids. I keep wondering how people knew that Lassie was trying to tell them that Timmy had fallen down a well. Ultimately, you have to rely on yourself first.
I've frequently mentioned the danger of falling tree limbs but frankly you'd have to be extremely unlucky for that to happen. Unfortunately, the places I go are heavily wooded and there's not much open area. High winds will make for a nervous night in a tent. I've never actually read or heard of anyone being injured that way.
Something else to consider is age.
Joints, balance, bone density, muscle mass ALL start declining when we reach 50.
A stumble that would have a 20 year old version of us laughing could well affect the mobility of 50 year old version of ourselves.
Even getting fatter has an effect as it puts more stress on our joints and increases our center of gravity.
I've had several instances where either someone in our party or someone we've come across has sustained an injury bad enough to make walking out on their own impossible.
Had a mate badly twist his ankle, fortunately i had enough wood, duct tape, cordage and bandages to make a splint and a walking crutch, took an absolute eternity to cover a few km to the road, but we managed to get out without needing to call SAR.
Another time a person in our party fell forward, wasn't particularly dramatic and it wasn't on particularly steep ground, but they happened to fall with their knee right onto a sharp rock.
That time SAR needed calling and she was driving off the mountain/hill in the back of a defender.
I've broken my arm and thumb on separate occasions while out mountain biking, managed to strap both up enough to ride out.
Had a mate break his collar bone when MTBing as well, he was able to walk to the nearest road and wait till i bought the car.
Had a couple of instances where it would have been foolish to continue the weather was THAT bad.
On both occasion i waited out the weather, but on both occasions i had my tent, sleeping bag etc with me.
To be 1000% honest i'm not sure i would have waited the weather out if i didn't have a tent.
I certainly would have continued longer.
I used to go out with just a bottle of water when i was a kid, even in areas i didn't know well.
The first time i did Ben Nevis i had a bottle of lemonade in my pocket and a pair of converse tennis shoes on.
It's really only after experiencing problems and seeing how often they occur that i've gotten more concerned on safety.
I've been cold enough that if i had flame thrower and 5 liters of petrol i still couldn't have made a fire.
So i try to give realistic problems a realistic solution rather than some dreamed up fantasy that some TV producer thought would be good for ratings.
Hence not wanting to rely on finding fuel for a fire, shelter etc etc.
If it's not in my rucksack and i don't know 100% i can recreate it or use then it's just not a safe option for me.