Where does this weird expectation come from that you can basically achieve your goals in a 2 week air campaign?

If the US wanted to they could probably do a lot of damage but, as you can see in Ukraine, taking over a country is a whole different thing. Unless you're willing to go in with the army and are willing to lose a LOT of people. And even then it'll take months or years for a single country

From every US administration that’s started a war since about 1945.

And we give em a couple decades to catch up.

....before being nuked for messing with the capital...

Sounds like a great idea!

Remember, part of the reason the war in Iran is going so poorly is because it has abysmal approval ratings among the US populace across the board, and wasn't even approved by Congress. (turns out, most people have middle-east fatigue and don't want to die for Israel.)

If another country actually tried to invade us, essentially the first time in a century we would be fighting a war to defend ourselves instead of one where we're going on the offensive, you would see the approval for a counter-attack be through the roof.