it's not only that. trauma also hits differently if you are the only one experiencing it vs everyone around you. the group experience itself makes trauma easier to handle.

i believe (i don't know enough about this) a big factor is also how your peers treat you after you experience trauma. think about veterans coming home, friends and family don't understands what they went through. they can't talk to anyone because nobody takes them seriously, even to the point of disbelief, or they blow things out of proportion, make them into bigger thing than what the person actually experienced. maybe the veteran doesn't feel any pain, but they tell him that he should. either way, the veteran is completely misunderstood. (again, this is not backed by any knowledge of psychology, just a guess based on some personal experience)

so because in the past everyone experienced the same brutal life (except the land lords or otherwise well off), it wasn't as traumatic as it would be today.

I think you touch upon something sound, there - while societal and group trauma is certainly a thing, we generally call it culture.

On the individual level… for me, certainly, the hardest part of dealing with my particular flavour of living nightmare was that literally nobody could relate to it, and the others who went through it are scattered to the winds. When you explain something painful and the response is “I would have considered myself lucky to be in your situation” or words to the effect, it’s a rather lonely thing.

In the past, if you said “the baron came and murdered my child on a whim”, people would likely sympathise - in today’s society… well. We have such a buffet of lives and possibilities that comprehension of the worlds of others is increasingly challenging.

Solzhenitsyn put it well - can a man who is freezing understand one who is starving?