I would suggest that the absurdity of high numbers was done for political reasons. If we were to assume as some scholars do that these texts were written during the time of the Greek occupation then the intent would be to make David and Solomon look mighter than Judea's conquerors. There is an assumption that Jerusalem was the origianl city of David. Of that I am not too sure.
"On Earth as it is in Heaven, the Cosmic Roots of the Bible" available on the Amazon.