These are some reasonable observations. But accounting for the origin of the personal resurrection concept is one thing; accounting for the idea of a dying or suffering and rising or triumphant deity is another. Greco-Roman cultured cornered the market on the latter, and the notion of a dying and rising god is anathema to monotheistic Jews who would have regarded it as blasphemous. True, Jews had the idea of a suffering servant or spiritual messiah, as in Isaiah 53., which was just a personification of Jews' historic hardships. But again, the concept of a dying and rising god is much older, going back to the worship of natural seasons and cycles of vegetation.