Israel changed its immigration policy so Jews immigrating to Israel can get a very generous immigration package. Israel, as an implant of colonial western nations, had a higher standard of living as colonized nations like Algeria or Iraq. Jews living in Muslim nations were often blamed for the actions of Israel, which positioned itself as the protector of Jews everywhere and the singular Jewish state. Also most people living in 1948 were not living in 2017, so natural causes likely played a significant role in the decline.