Israel is similiarly lucky that it is surrounded by neighbors with US bases that can intercept missiles and drones before they get to it. All of its more competent enemies are very far away. In a different scenario there'd be no motivation for a country like Iraq or Jordan to help.

They can afford to try to destroy Iran's offensive capabilities because in-between countries allow their airspace to be used.

Wars are usually between neighbors. If a neighbor has a huge stockpile of drones they can launch a first salvo that'll overwhelm whatever defensive capabilities the other country has before they even get to the point of destroying launchers/manufacturing.

Threats of massive drones strikes are the closest deterrent a country can get to nuclear weapons without developing nuclear weapons. If Iran had 5 million drones instead of 50 thousand this war wouldn't even be happening.