The question whether or not Jesus himself actually spread a message of universal love becomes rather tedious IMHO. We can never know for sure how much Jesus preached universal love and so it seems rather pointless to spend too much time speculating about it. However, in the next chapter about Paul, we finally see where Wright is going with this line of thought. This chapter becomes somewhat tedious as well, casting Paul as a sort of Roman version of a frequent flyer businessman, spreading the word of Jesus. The main thrust of all this is to suggest that the idea of universal love came not from individuals like Jesus and Paul, but from conditions "on the ground" as Wright likes to put it. The Romans had built a vast network of roads, opening up new vistas for commerce and mingling of cultures, and the message of universal love would have found a new non-zero-sum niche in an ever-widening moral circle. Like Philo before him, Paul may have seen the wisdom of assuming a live-and-let-live attitude in order to deny the enemies of Christianity a rationale for persecuting them.

"Paul was part of a religious minority that was widely reseted and that, if it didn't demonstrate restraint amid provocation, could be persecuted to the point of extinction. In that sense his situation was quite like Philo, another adherent of a suspect faith in the Roman Empire of the first century. . . . Certainly Paul seems to have known that an onslaught of kindness can frustrate the enemy by denying him what he most wants: a rationale for hatred, a pretext for attack." (285)

Wright tries to create a jaunty tone by using the language of commerce, equating opening churches with francising McDonalds or Taco Bells. I guess he does this to relieve what he fears may be the dryness of his subject, but there is in fact some similarity. All of the factors you mention come into play with the spread of Christianity beyond the borders of Israel. They don't to me appear sufficient in themselves, though, to explain why Paul carried out this difficult mission. He didn't create the Christian church, but it was he who determined that it would be a Pauline Christian church rather than that of other prominent contenders that Wright talks about. Facts on the ground might seem in retrospect to have strongly influenced Paul's emphasis on the brotherhood of Christians--regardless of ethnicity or nationality--but it doesn't for me explain the whole phenomenon. We should note, too, that even with Paul's theme of love, the universalism is not particularly strong; it's Christians loving Christians.

So I think at this point I find something missing in Wright's analysis. It may be simply desire, strong belief, idealism that accounts in part for love figuring so prominently. At any rate, it's a good thing, thought not the ultimate development in universalism.