That’s all just speculation. And speculation is idle.
But if we operate at several steps removed from factual reality, after stacking up a dozen of these unevidenced assumptions, then I would say the scenario proposed is still much less likely than that Paul and Christianity date to the 50s B.C. for which, unlike this stack of conjectures, actually has some evidence in its support—just nowhere near enough to believe. Therefore, a fortiori, this imagined scenario is even less likely.
We must then add to this that the pre-Gospel sources (esp. the authentic Paulines, 1 Clement, and Hebrews) explicitly have no knowledge of the Jewish War ending in 70 (ending the Jewish temple cult, even leaving Jerusalem an uninhabited ruin, and radically changing the entirety of Judaism and its status with Rome), so they cannot date later (see my demonstrations of this in On the Historicity of Jesus), which conclusively rules out any theory that Christianity arose after 70.
For some reference points see my article on the historicity of Paul and my comments on dating relative to Aretas in comments elsewhere, and my article on Lena Einhorn on the Claudian Christ Theory. Links to which:
That’s all just speculation. And speculation is idle.
But if we operate at several steps removed from factual reality, after stacking up a dozen of these unevidenced assumptions, then I would say the scenario proposed is still much less likely than that Paul and Christianity date to the 50s B.C. for which, unlike this stack of conjectures, actually has some evidence in its support—just nowhere near enough to believe. Therefore, a fortiori, this imagined scenario is even less likely.
We must then add to this that the pre-Gospel sources (esp. the authentic Paulines, 1 Clement, and Hebrews) explicitly have no knowledge of the Jewish War ending in 70 (ending the Jewish temple cult, even leaving Jerusalem an uninhabited ruin, and radically changing the entirety of Judaism and its status with Rome), so they cannot date later (see my demonstrations of this in On the Historicity of Jesus), which conclusively rules out any theory that Christianity arose after 70.
For some reference points see my article on the historicity of Paul and my comments on dating relative to Aretas in comments elsewhere, and my article on Lena Einhorn on the Claudian Christ Theory. Links to which:
https://www.richardcarrier.info/archives/7643
https://www.richardcarrier.info/archives/14255#comment-26774
https://www.richardcarrier.info/archives/14255#comment-26303
https://www.richardcarrier.info/archives/11048