Too often, however, at least from the point of view of this chapter, the literature has failed to begin at the beginning. It is one thing, for instance, to explicate the angelic terms in which some thought about Jesus, quite another to explain why anybody found those terms appropriate in the first place. And so it is with other christological conceptions and titles. Why did Jesus draw them all to himself? (pp. 241–42)
My inclination is that this question (viz., Why did anyone consider Jesus worthy of exalted christological titles in the first place?) is too often begged and too seldom asked. It makes sense to me, for instance, that some Jews thought of the messiah in terms of Davidic descent, and so Jesus' followers created/expanded the Son of David motif in the Jesus tradition. But scholars who push this perspective to its ultimate end—that the historical Jesus never thought of himself in terms of Davidic descent—have traditionally been content to demonstrate how the attribution of Davidic descent developed in the tradition and to never ask the ultimate question. Why did anyone think that Jesus, without any precedent of Davidic-ness in his teachings or actions, ought to have been framed in terms of "Son of David" christology?
I asked a similar question in chapter 5 of Structuring Early Christian Memory: Jesus in Tradition, Performance, and Text (T&T Clark International, 2010).
Given the ubiquity of research that traces how Jesus' followers reconfigured him to address their later concerns, we ask a question otherwise unasked in 'historical Jesus' research: why Jesus? Why did Jesus' followers choose him as a vehicle to address and conquer their concerns? (120; see also p. 136)
Jews in antiquity demonstrably turned to exalted figures from the past—whether real or mythic—and exalted them even further. Moses not only died on Mt. Nebo across the Jordan River (so Deuteronomy) but also received burial from the LORD or one of his angels. Enoch didn't just walk with God (so Genesis) but received a grand tour of heaven and God's plans for the future. The Patriarchs not only multiplied the blessing of Abraham from a single heir among multiple offspring (Isaac but not Ishmael; Jacob but not Esau) but then left behind their own blessings (in the form of Testaments) that pulled back the veil of the future ever so slightly.
And so on. But what stands out is that the early Christians did not reach back into the ancient and/or mythic past to pick out their hero whom they would idealize. Instead, they picked a not-unproblematic figure from recent times, whose earthly associates were still available (at least to anyone in Galilee and/or Judea), and whose fate did not exactly commend him to exaltation. This isn't an air-tight argument for the historical reliability of the Jesus tradition as preserved in the New Testament. But it does present problems for anyone who thinks that the NT traditions about Jesus have very tenuous—if any—connections with the historical man from Nazareth. Something about that man made it possible to apply exalted titles to him and to convince others to accept those titles on his behalf.