I ran this theory past Richard Carrier in a recent comment on his blog and he didn't buy it. He suggested other reasons why Paul wouldn't and couldn't have split off on his own
Paul’s communities were probably supporting Jerusalem because he didn’t form them. Paul doesn’t ever explicitly say he did (neither does Acts, incidentally: it mentions making converts, but never being the first to have done so, or having established communities; Paul’s letters, meanwhile, were written twenty years after Jesus is supposed to have died, and thus the churches he is writing to could well have existed half a generation before Paul came and expanded them with new converts). Thus Paul may well have just come to already-existing congregations, teaching a new gospel (just as Apollos then did, which Paul then has to accommodate, Paul then being in the same position Peter and gang were with respect to Paul).According to Carrier, Paul needed both the support of the entire church network and the endorsement of the apostles in Jerusalem.
Although I appreciate Carrier's insights and look forward to his book outlining his theories on mythicism, I am doubtful that I will be persuaded that mythicism is more than one of a number of possible explanations for the origin of Christianity. It may well be that rather than forming communities, Paul brought his message to existing communities, but I don't see any way to be sure. For every "it may well be," there is an equal and opposite "it may well not be" (or at least a comparable one).
Paul may well have needed the endorsement of the Jerusalem gang to carry on his work among the gentiles, but there is a key point that makes me question that whether that was so. Jerusalem called for the circumcision of converts and Paul didn't. I cannot help but think that this would have given Paul a tremendous amount of leverage. In any conflict between Paul and the gang in Jerusalem, the Galatians would have a strong motivation to take Paul's side.
Carrier imagines a relationship in which Paul is like the loan shark who seeks permission to operate within the local mob boss's territory, in return for which the mob boss gets a cut of the profits. While that may well be, I think it is just as easy to imagine a relationship in which Paul is one mob boss having a sit down with another mob boss in order to establish that one of them gets Brooklyn and the other gets Queens. When Paul writes "they recognized that I had been entrusted with the task of preaching the gospel to the uncircumcised, just as Peter had been to the circumcised. . . . James, Cephas and John, those esteemed as pillars, gave me and Barnabas the right hand of fellowship when they recognized the grace given to me," (Gal. 2:7,9) I hear Tony Soprano and Carmine Lupertazzi divvying up turf.