I always find it amazing that we can accept the epics from Homer as being accurate unquestionably even though they were passed down by word of mouth for centuries before ever being put onto paper; but as soon as we get to the Gospels, God forbid they were written after the fact
Before we talk about the Gospels lets talk about the compilation of the Bible. The Bible wasn't compiled until a few centuries after Christ at earliest. What was going on at the time was there was a group of heretics called the "Gnostics" who believed all kinds of weird things. Anyway, they were spreading their own works and so the Christians at the time got together, went through all the texts, sought the advice of some wise guys called the Church Fathers (some of whom were dead by this point, but their writings were full of guidance), asked God for some direction and viola we have the Bible.
Now, to the Gospels. For the first few decades of Christianity there was little for the Christian to worry about because they were considered to be the same as Jews. Until the Great Jewish Revolt (66AD-70something AD) because the Christians did not participate in it against the Romans than after that the Christians started to have problems with the Jews and later the Romans as well.
One can guess a few things:
-It may not have been until that Revolt when the Gospel writers saw the need to put their words to paper.
-The Twelve Apostles were also being martyred around this time, so there goes one's main primary sources on Christ.
-The Gospel writers probably realized that if they did not write what they knew than later generations would probably have a harder time of knowing who Jesus really is and what He did while He was here because, after all, they witnessed some of what He did, they were very educated as well and they knew that they too would die one day and leave a lot of people without some bit of knowledge of Christ if they didn't write things down.
Just my thoughts. I highly doubt it is a grand hoax.