A discussion on the roots of the Jewish culture

When talking about the Documentary Hypothesis, some people feel that this a controversial view.
Of course, for me, this way of looking at the source of Torah is not controversial at all, in fact, that is the only way to realistically look at it. As many have pointed out, it does not make the text less “sacred”.
The sacredness comes from the fact that a people has believed this for 2500 yrs and continued the tradition, although it has changed a lot,
So, the answer to the question: “How come the Jewish people/culture has survived when the Egyptian, Babylonian, Greek, and Roman and other cultures have died?” is what? The ability to adjust? The belief in a monotheistic God? Some orthodox would say “it is that monotheistic God who sustained us”. My thinking is since the existence of a monotheistic God is controversial (to put it mildly, thousands of years of wars and millions of dead in “his name”) a more general statement can be made that is “easier” to "prove":
“The Jewish people has survived all those other cultures because of a continuous belief in a Monotheistic God”
Note. This statement does not address the existence or non-existence of God. It merely states that the belief in such a God, in itself, has helped sustain this people/culture.