Are you suggesting that all the gospels were written for popularity rather than truth? Excellent point! There are strands of the real story and real facts riddled within all the gospels, but Christians have edited, added to, enlarged, exaggerated and even included outright deceptions in order to make their story appeal to their audiences.
I call it 'reversing-into-truth'. I have no doubt that Christians reversed into the truth of the oral traditions about Jesus, just as I suspect they reversed into Josephus's mention of Jesus, just as they reversed into pagan meeting places, pagan festivals and anything else which might help their objective.
Now, that isn't intended as an outright attack on Christianity, but rather an objective approach to investigating what Jesus's real mission really was.
@Tumah has explainred that the 3 great feasts were just that, festivals which Jews attended, and although a theological doctor explains that individual Jews might only attend one of those feasts in a lifetime (
http://www.jerusalemperspective.com/2392/ ) I suspect that Jews were pushed fairly hard to attend in Jesus's time, plus the possibility that priests' fees for providing remission of sins and cleansing were most probably extortionate. I see Jesus'sand John's attitudes to the Temple, Priesthood, Sacrifice et all as the genuine kernal in the story.
That's the point, by stripping away the popular deceptions, exaggerations, etc there may be a real story to find.