Divergent Genealogies: the Centuries Old Question

Why do the genealogies of Matthew and Luke differ so much? I have come to conclude that I don't know why. Of the answers that I've seen, I see none really more plausible than any other.

There is a typical response which says that Matthew follows Joseph's line while Luke follows Mary's line. Maybe so.

There is the Zelophehad explanation which says that Mary's father either only had one child (Mary) or that Mary was the oldest of just daughters (or perhaps a brother died at a young age). According to the Zelophehad Law (Num 27), the inheritance of the father would be passed to the eldest daughter in this case. Since Joseph was married to Mary and is the head of his household, Joseph is adopted as the 'firstborn' of Mary's father and so Joseph and Mary are entitled to the inheritance of Mary's father. Maybe so.

There is Africanus' Levirate marriage explanation (Deut 25) where the differences are due to Levirate marriages in Joseph's family (right around Joseph's father and Zerubbabel). Maybe so.

Some people throw up their hands and declare that one or both accounts are just totally fabricated. I'm not sure why this conclusion would be warranted. Plus, in first century Judea, what good is a totally fabricated genealogy?

Some just say Matthew and Luke came across or had access to divergent traditions. Matthew and Luke both received their separate traditions and that's the end of the story. Doesn't this just beg the question though as to WHY they are different. It seems obvious that both have different source material and the question is why or what accounts for the difference?

In any case, I don't know which explanation or combination to accept. I could conjure up one on my own that would be no less likely that any of the above but no better than the above either. Maybe Matthew had access to a private genealogy kept by Jesus' family and Luke had access to public archived genealogies in the Temple. Josephus tells us there existed a public archive (Life 1, Against Apion 1.7) for genealogies. Eusebius tells us families kept private genealogies that they would use to supplement the genealogies in the book of Chronicles (History 1.7.14). Matthew's genealogy follows the Chronicles very closely which might make me think his list is from Jesus' family and supplements the Chronicles list. Luke then would have accessed the public archives, perhaps through one of the priests who became a believer (Acts 6:7). Maybe the differences between the private family list and the public archives list was due to any combination of Zelophehad laws and Levirate marriages.

Well, genealogies are by nature very messy things. I have access to databases and internet technology and still have a messy time tracing family roots. I can imagine how much more difficult it would be keeping things nice and neat through troubled Israelite history. I'm content not knowing why exactly the genealogies of Jesus are so different. I'm content with accepting the message they drive home: Jesus is son of David, son of God, a man of high honor, and I catch Matthew's clever play with numbers to point out that Jesus is the son of David.