The links you provide, as far as I can skim, don't weigh in on the tradeoff.
Wholeheartedly agree with the sentiment and far too many kids these days are growing up raised entirely by electronics.
I recall my parents shutting off the electronics and forcing us outside, which was a huge boon. My dad was also always down to go on adventures and get dirty.
Climbing a climbing frame? Surely fine. A ladder? Most likely. Climbing a tree? Probably fine, though also depends. Climbing onto a steep roof? Uh oh. Soloing El Cap? I'll leave that to grown ups.
I think the paper addressed this but what we consider risky play now is so sanitized. I am pretty sure climbing a tree is more than fine even 30 years ago.
Is this still the protocol among anglophone children, or has it changed during the intervening decades?
Don't worry, all the damage is mental and won't manifest itself until I'm middle aged.
Kids breaking their legs all the time falling off of things has never been a problem at any point in history. This suggests that no effort is needed to ensure that it isn't a problem in the future. You don't need protections against things that don't ever happen.
So while I agree with what you are arguing for, I don't think your argument is valid by itself.
I broke my leg once in my youth, it wasn't that bad. Edit: I should remark though, that this was a very clean break, some it might not be representative of the average broken bone.