Has the US learned any lessons from the Iraq War?

I read this excellent editorial in Sunday's LA Times by Doyle Mc Manus.
Doyle McManus: 10 years later, lessons from the Iraq war - Los Angeles Times:

He cites the "second" Iraq war is one of the worst foreign policy blunders of our time.  I agree it was a huge, and very expensive blunder.  If the US now had all of the money we wasted on the Iraq war right now, we would not be having budget problems.  If we had avoided the Afghanistan war, we would be in "fat city" with lower taxes, better services, improved education, medical services etc.

His question:  "have we learned from our mistakes?" -- I don't think so!  I think our politicians have short memories, and do not take any action to correct previous mistakes.

I think there were other major mistakes in my "memory" --and one of the biggest was Viet Nam.  What were we thinking?  Another big one was protecting the Shah of Iran when he was about to die anyway.  He wasn't our friend.  I'm sure our government asked him to institute freedoms for his people, and to shut down his torture chambers, but he continued anyway.  I'm sure when he became ill, we asked or even begged him to set up a succession plan so there wouldn't be turmoil upon his death.  But he ignored us.  Why then, did we bring him to the US to die?  All that did was make the people of Iran hate us, and that hatred has continued now for decades!
I also think the Bay of Pigs and our treatment of Cuba was just crazy.  We should have aided Castro when he asked for help against Batista -- Batista was a corrupt dictator and, again, not a friend of the US.  If we had helped Castro, he would have been an ally and we never would have had the "Cuban Missile Crisis" or the "boat people" or any of the other problems that came about.