1) Every authority figure is telling the Iranian people to stay inside and wait.
2) Revolutions don't happen overnight, the same way that businesses don't succeed overnight, even though from far away it might seem that way.
3) Official Israeli statements estimate it could take up to a year after the war is over for a successful overthrow, even if everything is going according to plan.
The truth is there's a lot of people who want this war to fail, because it will align with their political convictions and hopes.
It is working on making itself larger cleansing whole areas around it and settling it.
Israel would probably be fine with a moderate government in Iran. A moderate Tehran doesn't encourage Hamas and Hezbollah to randomly lob rockets into Israel.
Even if Israel disagreed, a moderate Iran balances Israel in the region. An Iran that has beef with literally every single one of its neighbors other than Turkmenistan cannot provide that balance.