Iran is smart because it launched its first attack and second attack on 2 targets and that can't be defended. Israel has maybe two batteries of David's Sling and Arrow defending a high value potential target, no way can 2-3 batteries fend off 180-200 ballistic missiles.
Now if Iran launched their 180-200 ballistic missiles at multiple targets like airbases, ports, naval ports, Mossad HQ, Army bases, etc etc etc.... then likelihood of a warhead not reaching its targets is highly likely and Iran knows this. Israel's BM defense is spread out throughout the country. A David Sling battery has 6-8 launchers per battery and a launcher carries 12 missiles. An Arrow 3 has 4-6 launchers with 6 missiles per launcher so you start to see the problem Iran has if it attacks many many targets inside Israel with 200 missiles.
So if Iran retaliates after Israel strikes, Iran is only going to be able to launch at 2 maybe 3 targets to try to overwhelm Israel defenses. Unfortunately for Iran the warheads that got through hitting the Israeli airbase didn't do anything to stop Israeli operations. Conventional BM's are not efficient like aircraft carrying 2000lb jdams and other PGM's.