Anti Semitism can arise again. Conspiracy theorists have been scapegoating Jews for centuries.

Only racists promote ethno-states, there is no need for a state for every ethnicity.

I fail to see how Israel no longer existing affects the living conditions of a Jew in Melbourne

There are literally Nazis in Melbourne. That is why there was a law made a couple of years ago to prevent Nazi salutes. It is contained for now but it is not guaranteed as safe in the future. Jews in Melbourne would gladly use Israel as sanctuary if their life depended on it.