I disagree about being trauma naive as a society. Having a scientific understanding of trauma is separate from having phenomenological understanding of trauma, and I believe we have a large amount of knowledge and wisdom about the latter. I also believe there is a large repertoire of psychotechnologies that helped people to be trauma resistant or helped them if they had PTSD. We just lost contact with many of them and psychotherapy is perhaps the only dominant vessel for us in rediscovering those.

Peter Levine's most famous example is a polar bear that shakes a potentially traumatic stimulus off after being shot with tranquilizer. He argues even non-human mammals have the instinctive know-how to deal with trauma. Why humans would be lagging behind other than undue suppression of their instincts on how to deal with it? If anything, our modern society that puts so much stake at "being in control" is a hindrance to post-traumatic resolution than historical societies would be.

A crucial requirement for traumatic retention is a sense of loss of control that accompanies hyperarousal. No perceived lack of control = no trauma. In the context of combat PTSD, there is a large difference between modern warfare technologies and historical warfare in terms of the loss of control it induces (both for soldiers and civillians). At the very least, I would argue historic wars had more contextual meaning with them, fighting for one's land, nation, loved ones were more immediate and connected to the action, as opposed to being flown to a foreign country for less-than-well understood purposes.

Even for complex-PTSD, nuclear and even single parent households being a recent state of affairs, I would argue historically having multiple adult figures in one's childhood context prevented a problematic relationship with a single adult dominating the development experience of the child. Also those children had more access to natural world early on (unsupervised play time), developed competencies (e.g. working in the farm with parents) and afforded many other developmental freedoms, therefore likely to have developed trauma resilience. What was a rite-of-passage ritual supervised by the elders if not a training program for developing trauma resilience?

I would say it might as well be our current world that is more trauma-naive, trauma-generating and trauma-retaining than historical ones. We have the collective wisdom on how to deal with it, but insurance doesn't pay for it and you gotta show up at the office the next day.