I just read your tretise again. I like your questions. In fact I've asked a lot of them myself. You imply some conclusions that I'm not comfortable with however. We could draw some firm conclusions if all of the books that were ever written about everything were still available. But they're not. In the ancient, illiterate world I don't think many books were written in the first place. How many books do you think there were in circulation 2 thousand years ago? What did people write about back then? Who were the authors and who were the audiences? Why did they even write books? Did they get paid for writing them? Were there professional authors back then, like there are now?
You are uneasy with reaching the conclusion that Jesus did not exist, for we do not have a complete historical record of that time. That is true. We cannot resolve the issue of his existence with certainty either way. And I make no claim that I know it with certaintly. I do think he probably did not exist, but I am not dogmatic about that claim. (See The Jesus Puzzle for more information on why many think he did not exist.)
You say you enjoy reading the reported words of Jesus. That is all well and good. There are a lot of good ideas in the Q Gospel and Thomas, the two books that are believed to be closest to the timeframe of Jesus. And there are lessons to be learned from writers like Luke who built on this tradition. I am in no way saying we cannot learn from these books. The point is that there is no way to prove that these books represent the words of a single man named Jesus, the words of one man who used Jesus as a pseudoname, or a compilation of sayings of many people. When it comes to enjoying the moral lessons there, one can do that regardless of who had a hand in preparing those documents.