In fact, things got much worse for the Jews, especially after they launched a revolt between 66 and 73 CE, which did not go well. By the time the dust had settled, the Romans had destroyed the temple and expelled the Jews from Judea, beginning what we now know as the Jewish Diaspora. And without a temple or geographic unity, the Jews had to solidify what it meant to be a Jew and what the basic tenets of the religion were. This forced the followers of Jesus to make a decision. Were they going to continue to be Jews following stricter laws set forth by rabbis, or were they going to be something else? The decision to open up their religion to non-Jews, people who weren't part of the covenant, is the central reason that Christianity could become a world religion instead of just a sect of Judaism. And it probably didn't hurt that the main proponent of sticking with Judaism was James, Jesus' brother, who was killed by the Romans.