Was the Bible pieced together out of earlier manuscripts using scissors and paste? To answer this we need to leave aside the Bible, which arouses strong feelings one way or the other, and ask whether this is plausible in terms of older works in general. But I do not find this approach at all plausible when applied to the Iliad and the Odyssey, the Epic of Gilgamesh, or Shakespeare's plays, books I readily admit are neither God-inspired nor inerrant. There was once a literary fad that attempted to apply this method in general. It has long since passed away, outside of Biblical studies. There are good reasons for this.
People do not write books this way. That someone would write a book by lifting odd sentences or paragraphs virtually unchanged out of different manuscripts is incomprehensible. Most writers are simply not that humble, for one thing. Even in older times, where writers had a stronger idea of the need to stick to their sources then we do today, that a person should write something without putting it in his own words is extremely unlikely. Now if someone could produce for me the physical evidence, I might feel forced to consider such an idea, but I am asked to believe this based on the idea's own plausibility. And it is totally implausible.
Also, the criteria that are used to distinguish between different manuscripts, particularly in the Pentateuch, are found in other ancient Near Eastern literature, including inscriptions, where there can be no underlying manuscripts. For example, much has been made of the multiple names of God or other individuals in Scripture. Yet it was quite common in that culture for gods and men to have more than one name. The real question is whether it is possible to say with certainty, without tangible evidence, how a literary work was composed, especially in another time and culture. On the kind of evidence used here, would we not conclude that J. R. R. Tolkien or Charles Dickens or Robert Lewis Stevenson did not write many of the works attributed to them?
It would be tempting to claim that, if this is the best argument that can be made against Biblical inspiration, it is a great proof of Biblical inspiration. But this would not be fair. I am convinced that someone with less scholarship and more common sense could come up with a more plausible way not to believe Scripture. The truth is, that after putting this forth as the proven results of modern higher criticism, it is hard for people to back down. But that does not make their theories reasonable. Such theories regarding the production of literature may be interesting
to speculate on, but are dubious in the extreme. Whether or not anyone
claims that the literature in question was inspired by God.