Getting to my point, would Roman Emperor, Constantine convert to and decree that his vast kingdom follow him to believe in and follow a mythical Jesus?
yes. whether or not jesus was real, it was certainly an effective tool at the time.
Another point I want to make relative to your statement above is that Before Constantine, earlier emperors sought to stamp out Christianity because so many were turning from the pagan gods to Jesus. This, I understand included the burning of scrolls. Could this be a significant factor in explaining the absence of early manuscripts as well as mention of Jesus?
early manuscripts -- maybe. remember that the council of nicea basically established canon by popularity vote. the ones that were being used in the most churches, with the least opposition, in effect, won. that means many multiple copies of documents existed, not just one or two.
i think the single best explanation for the lack of manuscripts from shortly after the lifetime of jesus is the apocalypse. when he said "i'll be right back" they thought he meant within their lifetimes.
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