But to go along with the premise a bit…
If man had escaped in a pod from mars hundreds of thousands of years ago why would they go back to living in caves, talking in urrghs and rediscovering fire. Rather than just continuing to live in the scientifically advanced manner that they had been doing on mars.
Because a certain amount of infrastructure must exist before technology becomes viable. For example, you need a coal mine and an iron ore mine, to make steel to make a bridge. Then you need the steelworks. So even if you know how to make steel, you might not be able to do it. In fact, the limiting factor will be the population, so you might need to spend a while doing subsistance farming to support enough people, so then you can move to agribuisness farming so that those people can now concentrate on mining, and so on etc.