Technology

A full on invasion will be much more difficult than Irak. The US probably could do this but it's going to be costly, forever and very unpopular. US military would be bound up for a long time.

Good question what the goal is supposed to be now. Trump may just declare it over somehow.

I think the issue is that offense is harder than defense. A defender generally has the home advantage in terms of logistics, familiarity with the area and political will. The difference this makes is hard to estimate, and even harder so if you're not even aware of it. Combined with delusions of grandeur, this is a recipe for underestimating the enemy.

And call me a cynic, but I suspect neither Cadet Bone Spurs nor Major "Warrior Ethos" "Signal Chat" "American Crusade" Boozeth are entirely qualified to make high-level military judgements.

(Neither is my armchair general ass whose only education in the matter is some MilHist blogs and articles, but at least I'm not an actual general charged to actually make them.)

For Putin, I'm not sure. I'm disinclined to believe he's just ignorant about the tenacity a people under attack can develop, given Russian history, but I can only make unqualified guesses.

Either way, as you say, I wouldn't want to be on the receiving end, because a blunt and rusty axe still hurts, and they don't seem concerned about where they swing it and who's in the way.

But US vs. Iran war isn't total war for the US, like Ukraine vs. Russia is for Russia.

Only 8 US soldiers died, compared to likely hundreds of Iranians and most of exposed Iranian infrastructure. US didn't even deploy a single aircraft carrier.

Doesn't matter how advanced your weapons are if you have not enough money to use enough of them and not enough soldiers that would like to come and kill other people that can also fight them back. So, while the USA has high defending potential, it has not enough politically approved resources for a long occupational war. Only short quick operations are now possible, since the USA citizens are against the war and greatly affect the leadership authority of current government, so that it cannot waste money to launch a full scale war as it was before. Especially, because of this doesn't pleases oligarchs which have great leverage in this situation.