Most antiquities scholars think that the New Testament gospels are "mythologized history." In other words, based on the evidence available they think that around the start of the first century a controversial Jewish rabbi named Yeshua ben Yosef gathered a following and his life and teachings provide...
Okay look. I am an atheist, I think magical thinking in general and Christianity in particular are harmful and unnecessary.
BUT
I also enjoy learning about new testament history as a hobby. I've actually read the book How Jesus Became God that the article mentions, and they do a sneaky thing that annoys the shit out of me: they quote things being said by someone who disagrees with them that appear to completely demolish their own position, without quoting the explanation and nuance that inevitably follows. Ehrman obviously doesn't see the quoted text as a problem for the idea of a historical Jesus, and usually explains as much after saying something like that.
I won't nit-pick all the little over-simplifications, but I want to make an example out of one of them:
The gospel of Mark is thought to be the earliest existing "life of Jesus," and linguistic analysis suggests that Luke and Matthew both simply reworked Mark and added their own corrections and new material. But they contradict each other and, to an even greater degree contradict the much later gospel of John, because they were written with different objectives for different audiences. The incompatible Easter stories offer one example of how much the stories disagree.
The incompatible Easter stories are actually something many secular scholars point to as evidence in favor of a historical Jesus.
I'll go into more detail if anyone cares, but the broad strokes are this: the nativity narratives in both Matthew and Luke contradict not only each other but also known history and even basic plausibility. We're pretty confident they were both made up.
So, why? Why would two different authors working from the same source material both tell weird lies about Jesus' birth?
Well, the expectation of the Jewish public at the time was that the messiah would be born in Bethlehem. Mark doesn't talk about Jesus' birth, but it does say he was from Nazareth of Galilee. That presents a problem: how is this guy who people are calling Jesus of Nazareth also the messiah from Bethlehem?
That's where we get Matthew and Luke trying to smooth things over: Matthew makes up a story about how Jesus was totally born in Bethlehem, trust me bro but Herod the Great tried to kill him so Joseph and Mary hid in Egypt until he died but then his son took over Judea so they moved to Nazareth. True story bro.
Then in Luke, the author says that Joseph and Mary lived in Nazareth, but Caesar ordered a census of the whole Roman empire where everyone had to return to their ancestral homeland because reasons. So they go to Bethlehem because David was Joseph's... great-great-great-great-great-great-great-great-great-great-great-great-great-great-great-great-great-great-grandfather? Why they stopped at exactly twenty generations (and how the fuck Joseph would have known that before ancestry.com) is never specified.
Even if we grant miraculous intervention, these stories are both ridiculous on their face (at least, to a modern audience). If Jesus was fabricated whole cloth, why include these bullshit Easter narratives in the first place? Why not just say "He was born in Bethlehem" and be done with it? To my mind, these stories make the most sense as a post-hoc ass-covering to explain how the guy who was walking around calling himself "Jesus from Nazareth" was actually totally from Bethlehem the whole time.
I don't know that Mark having errors based on Old Testament prophecy necessarily means that the corrections in later gospels were fictionalizing a real event. That is one possibility. Another possibility is that the author of Mark wasn't as well versed in Old Testament prophecy as the authors of later Gospels, who worked to correct this.
Yours is not a terrible hypothesis by any means, but I don't think it's as cut and dried as you think it is.
It would have been translated once, directly from the Gnostic gospels that were found. But I'm not sure why that matters since they would be scholarly translations because they were found in the mid-20th century and the important thing is discovering what the Gnostics believed, meaning an accurate translation would be necessary.
I think you're confusing the Gnostic gospels with something like the King James Bible. It's totally different. We only knew what the Gnostics believed from secondary sources until the Gnostic gospels were discovered.
how the guy who was walking around calling himself “Jesus from Nazareth” was actually totally from Bethlehem the whole time.
Iirc the gist of the issue why they wrote that was the same as the problem with Jesus being descendant of David through Joseph - he needed to fit into the messiah prophecy. And he couldn't do that being a Galilean. Ancient Judeans were pretty chauvinistic overall in who is counted to even be a true Jew, remember the background of a tale of good Samaritan or how Herod was constantly bashed for being Edomite despite building spectacular center of worship.