There is certainly some reason why the Babel myth arose. But it might be no more than curiosity and the story-telling impulse. Why are therediffernet peoples with different languages ? what were those large, ancient ruins ? how do we fit those into our world-view ? Here's a story...
I suppose it is possible that the Babel story - like the Flood story - is derived from more ancient tales. But if there is an underlying factual basis for the story it lies well beyond those older stories and can't be reliably discerned from the Bible.E