My take on it would be that the gospel writers were not doing history. Luke might have been doing the closest of any of them, but he certainly altered his material to make his own points.
I also think that very little of the historical Jesus is recoverable. In the past I would have said that we know he was crucified, it is very likely he was baptized by John, and the Temple incident may have a historical basis. But that's about it. Today, I still would not say we can get much more in the way of words and deeds. However, I think, based on the earliest layer of Mark we can get insight into goals, motivation, and method of operation of the historical Jesus. In addition, I think that the layers in Mark can tell us a bit about the development of earliest Christianity.
The authors don't give us history, but the might mythologize a real person or event, and in addition they may respond to events around them, allowing us to infer the events from the response.