> It's been well reported the number of drones/missiles Iran fired has consistently decreased.

One way of interpreting that statistic is that they are running out of munitions. Another way is to consider that stockpiles are not running low, but the initial response was a collection of high-burn, uncoordinated, decentralized tactical actions after an attempted decapitation-strike disrupted top-down C&C. Now that the fog of war has cleared, and communication has been restored, a more strategic regime is now in effect.