IDK what you mean by people who have had no trauma. This is the stupidest take on DID and trauma I see (that there are people without trauma), and I see it everywhere. Do you consider children growing up in a school system where they are taught to fear gunmen coming in and killing them traumatic? I do, and we have millions of kids in the US school system going through that trauma even if everything else in their life is perfect (it's not, life under the capitalist system is traumatic in ways most can't begin to grapple with)

Life is full of things that an adult won't find traumatic but a child who doesn't know what it is or how to handle it will, and THEN the core feature of the disorder is amnesia.

I will say it again. THE CORE FEATURE OF DISSOCIATIVE IDENTITY DISORDER IS AMNESIA FOR TRAUMA. And yet I still get chodes coming around asking me to explain why there are systems "without trauma".

A broken arm at 8 years old is traumatic just as a missed meal a the right age, say 2yo, is traumatic. Small enough to be forgotten in amnesia, but still significant enough early on for it to have affected the child. By the time you're an adult, neither are generally considered "traumatic" because we've experienced or learned of MUCH worse things. Trauma Olympics sucks and we should stop doing it.

Having your caretakers not be responsive due to money stress is trauma to a young, developing child. Later they have already dissociated and their parents got their finances together, so they were attentive and the child forgot. Did the trauma not happen?

Please don't pretend like everyone on earth makes it to adulthood without some form of trauma. It's incredibly ignorant of reality.

If (by your definition) everyone has trauma, how can you say trauma causes anything? You can't really establish cause and effect for something that literally everyone has.

Genetic and biological factors (from the 2nd paragraph of the Wikipedia page, as you so helpfully pointed out above) play a role in the body's response to trauma.

Everyone has trauma, not everyone has DID from it, and that's where those factors come into play. Just as not everyone has red hair or the genetics for schizophrenia.

In the absence of trauma one can still be schizophrenic due to neurochemistry. DID does not form in the absence of trauma, but we cannot prove that because we cannot purge trauma from life.