I have many reasons to disbelieve the Gospel history of Jesus especially my scientific background, but Nazareth is a convenient point to concentrate on because the existence of ancient communities is easier to establish than the activities of religious teachers.

Most rational Christians and other religious people concede that the Bible or other scriptures could have significant errors in them, some will even admit there could be serious lies, but none I know will seriously consider that the life of Jesus of Nazareth may never have existed except in the minds of the Gospel writers.

If it can be shown that the city of Nazareth did not exist during the days of Christ then it brings to better focus the question about Christ's historicity. Accepting the possibility that Nazareth may not have existed for Christ to be from opens the mental doors for many rational Christians to consider that other critical ideas in the Gospels could also be false (miracles, resurrection, etc.).

According to Zindler's study of the archaeological and historical evidence, Nazareth was apparently a necropolis prior to the fall of Jerusalem in about A.D. 70. As I recall, archaeological evidence suggests that a community was started on the site about the 2nd century (100s), but history shows that it was not known as Nazareth until something like the 4th century (300s).

The place that came to be called Nazareth was evidently not a community during the days of Christ. It does not appear to be as you suggest (like the "Star Wars" example) that Christ was from a place that LATER came to be called Nazareth, unless his family were essentially the only residents with his father's carpenter business located above or in the catacombs.

If you can find flaws in Zindler's conclusions I would be interested in hearing them.

http://atheists.org/church/ozjesus.html