That arrogance cost the lives of thousands of American soldiers in countless illegal American invasions over the last 50 years.
Most of the casualties were on the ground, and due to enemy switching to asymmetric methods of warfare. The manner in which Muslims choose to fight these days, is utterly cowardly and in stark contrast to the principles of Battle of Badr.
Anyways, US will
steamroll Iran in a "conventional war." Their is no shame in admitting this, because this is situation of majority vis-a-vis US.
The US wasted $6 trillion+ of taxpayer money in their useless invasions of Iraq and Afghanistan post-9/11 attacks, two countries that had nothing to do with the 9/11 attacks whilst 15 of the 19 terrorists were Saudi citizens (as was the mastermind - OBL).
Your claims are completely off the mark (and charts).
Costs of these expeditions are high due to massive logistics requirements of a sophisticated war-machine (stretching all the way from US mainland to the battlefields), and due to push for political reforms in Iraq and Afghanistan respectively.
Total cost of operations, and rebuilding efforts, in Iraq = 1.1 Trillion USD mark (2003 - 2018)
Total cost of operations, and rebuilding efforts, in Afghanistan = 1.1 Trillion USD mark (2001 - 2018)
Al-Qaeda Network was responsible for 9/11 event, and its base of operations was in Afghanistan at the time (with legs in Pakistan; unfortunately). US invaded Afghanistan to eradicate this regime from Afghanistan (and Pakistan), and fulfilled this objective by 2011.
Al-Qaeda Network was a multi-national regime, and recruited individuals from all over the world. Why should KSA be held accountable for 9/11 event due to nationality of individuals involved? KSA did not allow Al-Qaeda Network to establish its base of operations in Saudi territory, but Afghanistan (under Afghan Taliban) did.
Afghan Taliban, in its current form, have unanimously decided that it will NOT repeat mistakes of Mullah Omar, and Pakistan have also adopted a strong anti-terrorist drive in current times. US have driven the message home in this part of the world, if you ask me.
Question is; have Iran learned any lesson or not?
I admit that US should not have victimized Iraq; this expedition was completely unnecessary and had no justification. On the bright side, Saddam Hussein, and his Ba'ath party, are HISTORY, and Iraq seems to have embraced democratic reforms which would be good for its masses in the long-term (Shia; Sunni; Kurd - each have a say in Iraqi affairs now).
On the flip side, these expeditions created jobs for many, American Military Industrial Complex flourished, and US have secured many lucrative deals. COSTS and BENEFITS - both should be accounted for in an assessment.