I was planning to address in greater this oft-repeated claim about the alleged "two generations" that are needed for a myth or legend to be established. However, Kris Komarnitsky at The Bible and Interpretation website has done a good job explaining why it is flawed. Here is the first paragraph:
"One major topic that impacts on the reliability of the Gospels is the rate at which myth or legend can grow over time and displace the historically accurate accounts of events. Some argue that the Gospels cannot be mostly legend, as many scholars have proposed, because that would require a myth growth rate that is implausibly high given their relatively early composition in relation to the events they claim to recount. For example, New Testament scholar William Lane Craig says, “One of the major problems with the legend hypothesis…is that the time gap between Jesus’ death and the writing of the Gospels is just too short for this to have happened."
You can read the rest at: Myth Growth Rates.