I can tell you this for certain, breaking a hip over the age of 65 is a virtual death sentence. Best case scenario, the patient manages to get around with a walker - most will end up in wheelchairs permantly.
I have to wonder about the accuracy of this. My grandmother broke her hip when she was 88 years old. She had to have a hip replacement, spent about 6-8 weeks in a rehab facility (with physical therapy and occupational therapy to make sure she could perform basic tasks around her house), and then went back home, where she lived alone. A few months later she fell again, and at that point it was decided that she shouldn't live alone anymore (after she refused home health care).
She lives in an assisted living facility, but it's the lowest-level type of care available (basically, they do meals and cleaning, sit in the bathroom with her while she showers, etc., but no nursing care). She'll be 92 in December. She gets around with a walker, and she has pretty bad memory issues because of the anesthesia with the surgery (short-term memory is crap most days, but long-term memory is fine). For 92, she's doing well.
I have an aunt who broke her hip around the time she was 80 (I think she's in her mid-late 80s now). She did fine for quite a while afterward. She uses a walker now, and she's gotten pretty frail, but for a couple years after she broke her hip she didn't really have any problems.
I think mobility is definitely an issue for elderly people who break a major bone (though I've never known anyone who ended up confined to a wheelchair, most were either forced to use a cane or walker), but I don't think it's a "virtual death sentence" by any means. That might have been the case 20-30+ years ago, but I don't think it is anymore.