Children can often adapt to hardship. What they struggle with is extreme unpredictability.
One reason childhood instability can be more damaging than poverty is that it's an evolutionarily novel stressor that children's brains aren't equipped to handle.
Poverty has long been the default in human societies.
But being raised by a shifting cast of caretakers, many of whom disappear from your life, is not. Children require stable attachments to develop properly. Without them, things go wrong.