Let's say that Jews were not expelled from the Palestine by a Roman Empire and largely remained there (which means no Diaspora).
Wouldn't it be likely that later, they would be conquered during Arab conquests and, possibly, converted to Islam, basically becoming what today's Assyrians or Berbers are? Or maybe more like Kurds?
Discuss.
I expect quite a few did.
It's a standing joke that if everyone whose ancestors were Jews was still a Jew, they would be the biggest religious group in the world. Quite a few converted to Christianity, willingly or otherwise, from the Roman period onwards, and no doubt many in the Moslem world embraced Islam. Today's Jews are descended from the hard core who refused to do either.
