20 Years is a Long Time
Thanks to Mark Goodacre for mentioning an article by Paula Fredriksen I wish I'd read before. From it:
"From its inception, the Christian movement admitted Gentiles without demanding that they be circumised and observe the Law...until 49 CE, evidently... What had changed between c. 30 and c. 49 CE, and why? Posing the question puts the answer...The kingdom did not come. Time drags when you expect it to end. Put differently, millenarian movements tend, of necessity, to have a short half-life. As the endtime recedes, reinterpretations and adjustments must reshape the original belief, else it be relinquished to unintelligibility or irrelevance." ("Judaism, the Circumcision of Gentiles, and Apocalyptic Hope", pp 558-559)Dale Allison couldn't have put it better himself (the part about millenarian movements reinterpreting things over time to cope with broken failures), though even he apparently missed what Fredriksen sees too clearly about the Gentile issue: that in Jewish belief, Gentiles turn from idolatry at the apocalypse without converting to Judaism. When the kingdom comes, Gentiles will be saved as Gentiles: "they do not," says Fredriksen, "eschatologically become Jews" (ibid, p 547).
That's what Goodacre is saying: "the early Christian inclusion of Gentiles into the people of God coheres with apocalyptic hope of the period, and it is a mistake to confuse inclusion with conversion". Only two decades later was conversion (circumcision, the "works of the law") starting to be required of Gentiles -- as more and more of them were joining the church, and as more and more the kingdom just didn't come.
Evidently, Paul wasn't ready to give up on the apocalypse as much as the pillars. :)