The people in the future were grossly underarmed
I noticed the people of the remaining future civilization were grossly under armed. It appeared that all they had in the way of firearms were some small, semi-automatic pocket pistols. No one had assault rifles or squad light machine guns. Any of that would have made a huge difference in fending off the vicious mutant bands.
They wisely programmed their androids for non-offensive combat capability and only limited self-defense ability. That prevented any android malfunctioning and turning on its creators. But in the end it limited their androids' overall group defense utility.