To destroy any Iranian military facilities, infrastructure, military industry, etc., the Americans don't need to literally descend from the sky onto Iranian soil; they can do it all from the air.
In American military strategy, the Air Force plays a primary role, but in the case of Iran, it is currently practically the only role. (If they sometimes sink Iranian warships with ballistic missiles, they do so purely spontaneously, apparently for training and even as a joke (in the last three days, the Americans have sunk 30 Iranian, so to speak, warships!)
The Iranian ayatollahs and the military under their command have made many mistakes...
Look, if you have a huge land army and you've chosen Israel, which is 1,000 km away, as your enemy, then of course you should take control of Iraq and Syria, and preferably also Lebanon, Hezbollah, and if you also want Yemen, that's perfectly fine. Iran has done just that: hundreds of thousands of Iranian proxy forces have been stationed in all of these countries. For 10 years, Iran has been building up its military infrastructure in Syria, right on Israel's borders. Israel has been primarily focused on destroying them all this time.
But, unfortunately for the ayatollahs, the main component of the Israeli armed forces is the Air Force. With its Air Force They destroyed Iranian forces everywhere, just as they are doing today inside Iran.
But Iran has no air force or air defense!
As if it didn't have enough enemies, Iran was also in conflict with America, Israel's strategic ally.

That's unreasonable.
In short, Iran had great ambitions but little ammunition.
This often ends badly.