Bingo! That is it in a nutshell.
We did much better in Germany and Japan post-WWII. The troublesome distinction, of course, is that Germany was not surrounded by Nazi states and Japan stood alone with its militaristic history - they were not surrounded by fellow-believers and it was much easier to crush those cultures to dust.
How to deal with Iraq after the shooting stopped was/is more problematic and, aside from the courage to take forceful steps, was perhaps beyond our current beliefs and skill set.
We also had to occupy German and Japan for years, before they were able to be independent again.
You think we’ll ever occupy Russia like that?