Iran had most of their command and control wiped out by precision strikes. Some how Mossad managed to know exactly where each of them are, and despite Iran having advaanced intel, did nothing to take precautions.
Mossad managed to build up stockpiles of missiles and drones inside Iran which they used to decimate Iran's AD.
And now, there more than a few sources saying just how thoroughly the IRGC, the premier force of Iran, is penetrated from top to bottom.
And wars aren't fought like the old days. Israel has practical air superiority over Iran. They're slowly escalating. I didn't get very excited after I found out what the targets were. No, taking out a few apartment buildings and killing 4 people isn't considered appropriate retailiation for having your country's upper echolon wiped out, your military degraded and your economy, military, population destroyed.