Well, it turns out that such a claim has no actual historical data on its side. In fact, in regard to the credentials of those who hold this "mythicist" view, Bart Ehrman makes this point (quoted from his HuPo article here):
"These views are so extreme and so unconvincing to 99.99 percent of the real experts that anyone holding them is as likely to get a teaching job in an established department of religion as a six-day creationist is likely to land on in a bona fide department of biology."Of course, Dr Ehrman is no friend to evangelical Christianity. This is what we call "hostile witness testimony," where someone on the other side of the debate is making your point for you. Such a testimony carries more powerful weight than if it came from an evangelical scholar.
So, for what it's worth, I think we can close the case on the question of whether Jesus was a myth.