Before settled agriculture, there were risks of all kinds for the men and boys, related to leaving the confines of the small groups which cohabited (cave, tree, island, village, what have you), and as someone pointed out, death in childbirth was a big risk for the teenaged girls and the women. It seems to me that the main consequence of short lifespans as described would be that affinities other than direct ancestry/descent became all-important, hence the rise of tribal groups.
Once lifespans increased — standard as settled agriculture and the sodbusters took over — immediate family (and greater personal privacy) became important and dominant. Communal living fell off, and the village — which has existed in some form for 100s of 1000s of years, based on the patterns of postholes — became a collection of family domiciles of various kinds. Villages started to have common defense, grew ever-larger, merged with neighboring growing villages into cities...
I guess one more thing to consider - and something the bones might have something directly to say something about - is the longevity of teeth.
I would think that a toothless primitive man would be pretty much of a goner. And there would probably be all sorts of reasons to lose teeth.
I think Inuit would get cast out on the ice floes when they lost their teeth.
If you tended to lose your teeth around age 30 that would probably have a good deal to do with longevity.
Probably the transition from hunter-gatherer to agriculturalist would change the entire survival equation.