Non-zionist Jews have been leaving Israel whenever the opportunity rose. This war was just an accelerant for further emigration.

The only ones who choose to stay back are folks fresh into Aliyah, who might've received a lot of incentives from the government to settle in the illegal West Bank settlements. Or those who really believe in Zionism. The former are typically guys who couldn't make the cut even in their home countries, so they're certainly not adequate replacements for the ones leaving.

Not to mention, it's mostly the liberal cities like Tel Aviv which have faced the brunt of Iranian barrages. Jerusalem has been barely hit. Folks staying in those cities, working actual jobs contributing to the economy and not Torah studies, are likely the ones leaving - I know many of my acquaintances who've left Tel Aviv for the US or Dubai.