Jonathan Drake: "As an example, the people who joined the Christian movement by the thousands..."
Why should we assume that there were thousands regardless of what the Bible claims? History does show that Christianity grew in numbers but that doesn't mean that several thousand were suddenly converted in a short period of time.
"Something very real, and very impressive was going on to cause such a drastic explosion of Jesus devotion."
I believe that something real and impressive did happen. Jesus was a charismatic preacher (guru, cult leader) who acquired a small number of super devoted apostles. They in turn started the ball rolling after his death.