A lot of European Jews were not killed in the holocaust. They were smart enough to see what was coming and they emigrated. In some cases they left most of their possesions behind and started over. There were more Jews that would have liked to leave but did not have the means or the documents. That will not be as much of a problem if things heat up in Israel.
Judge orders Jerusalem Gay Pride attacker to undergo psychiatric evaluation (Haaretz)
from the article: Despite returnee benefits push, more Israelis staying rooted abroad