^Salam brother. From what I read, Iran fields ballistic missiles of very high accuracy, such as the Fateh-110 and others, with CEPs of a few meters. The images of the recently unveiled Khalije Fars anti-ship ballistic missile impacting a targeted warship document this fact. As for hypothetical US counter-measures, one way to neutralize anti-ballistic missile SAMs, would be to saturate them with a large number of missiles plus decoys, all fired at once at the same target. Here, ballistic missiles will always maintain a comparative advantage, in that even 10 simultaneously launched, advanced ballistic missiles, will cost less to develop and to produce than a single newer generation Patriot or Aegis system.
I found the fact that numerous US bases are within range of Iranian artillery very interesting as well. This could offer the possibility to add another layer to Iran's deterrence against the US, if something like North Korean massive artillery tactics were to be used (the DPRK is said to field so many pieces of artillery, that Seoul could be devastated if each piece survives just long enough to fire a single round).