When one states that the city of Nazareth, for example, did not exist at the time the biblical book referencin?

When one states that the city of Nazareth, for example, did not exist at the time the biblical book referencing same was written and they claim that this is evidence of errant text. I am willing to cede to the explanation that the text was updated with the page of time and the advent of what is now formally called Nazareth to reflect the geographic area in question. However, how does allowing one this explanation not beg the question, “What other word(s) or pages were changed/updated from the earlier/original copy/version?”.