Imagine the following scenario (It’s fictitious, so don’t take it too seriously):
In the aftermath of the Civil War, before white southerners reintegrated into the Union, the US Supreme Court hatches a plot to make sure that there will never again be a civil war. Instead of making Constitutional Amendments, they decide to be more ambitious and change the text of the Constitution itself to reflect stronger Federal government and individual rights, with an eye toward demonstrating that the Rebs never realy had any sort of legal basis for their secession. The North goes along with it and the ‘revised’ Constitution replaces the ‘original’. Very few people know about the plot, and very few notice the changes. The defeated South is imposed upon virtually at will.
It’s only after a number of decades that legal scholars get wind of this conspiracy; they’ve compared the ‘original’ to the ‘revision’ and figured it all out. By then, there were 50 years of Supreme court decisions and interpretations working off of the new one. At that point, what should happen? Should the old one be reinstated – essentially erasing 50 years of development of the law? Should the new one be acknowledged de facto as the authoritative one, since it had been implicitly accepted as the authoritative one?
I’d imagine that you can see where I’m going with this: If one accepts the latter possibility, which is the most realistic and least disruptive, and probably the ONLY plausible alternative, then it says that the authority of a text derives not from its origin per se, but from how it was perceived and accepted.
In this light, all questions about the Torah’s authorship and human fingerprints that may have found their way into the text become almost irrelevant.