[sudosysgen]

The missile launchers that Iran relied on for many strikes are actually very big, and cannot be hidden in small civilian infrastructure. The US was unable to target them when they were coming out of the very well known and publicly located missile cities because there was no US aircraft that could loiter around them and wait for them to come out without being shot down - that's why the US sent drones to that task, which suffered unsustainable attrition.

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.