America knew how to do this once. Berlin is still in a sense occupied by American troops in that we still have bases there, and through NATO subsidize their defense and way of life.

You simply can't kill your way out of political conflicts into perpetuity, unless you truly plan on annihilating everyone. That is part of what makes the alcoholic running the DoD so galling. His thesis on places like Fallujah is essentially there wasn't enough bloodshed. Americans would be vacationing in Baghdad if only there had been more violence.

And the drones/missile have much more range than 300km. The Shahed-136 drone have a 2000+km range, which is significantly more than the combat radius of carrierborne fighters, even if you add reasonable amounts of refuelling.

The problem in the end isn't that it was impossible to strike every possible hiding site without causing massive casualities. It just wasn't possible. The US failed to durably damage Iranian installations. The backup plan was to exploit air supremacy to interdict whatever was coming in and out of those installations - that also failed. This was an operational failure of US military doctrine, that is unrelated to the tolerance of casualties. It is simply that US military planners overestimated their abilities and made assumptions they couldn't cash. It wasn't a case of casualty avoidance or whatever.

It's also questionable whether a ground invasion of Iran would be feasible to begin with. The Operational Art of War has a great series on the logistics of such an operation, it would be extremely difficult and would most likely require the US to send the troops... through the Strait of Hormuz to begin with.