The "Jesus myth" is the reason that Christianity was created. That does not make the myth true. The myth also has stories about chemical transformations, walking on liquid, amplyfying a fish to feed a multitude, rising after dying (and then dying again), etc., all of which are not possible or extremely unlikely (a virgin birth is theoretically possible) , but people who buy into the religion believe these stories.

Without these stories. Jesus could have been some random criminal who was executed by the Romans. The religion grew out of proselytizing by a small group of "apostles". It is faith alone that created the religion, and it is faith alone that keeps it alive. And that faith is based on unverifiable myths. There may indeed have been some guy named Jesus who claimed to be the messiah - history is inundated with crackpots who claim to be a god or the hand of a god. But the Jesus myth is about more than some random carpenter, and we know that most of it is false. Religions don't need truth. They only need faith.