Your example is using a situation where we primarily just gave money over a relatively short period of time.
We didn't set up shop there.
The Marshall Plan was in place from 1948 to 1952.
The Japanese occupation and reconstruction ended in 1952 as well.
Our reconstruction efforts (aka. primarily check writing and loan giving) activities primarily ended within about 10 years from when Pearl Harbor was attacked which was the end of 1941.
In comparison, we've been in Iraq and/or Afghanistan for over 13 years now, well past our entire involvement in WWII including helping rebuild SEVERAL foreign nations spread out all over the world.
In other words, bad example.
We simply did not destroy enough infrastructure to have to rebuild for that long.
We are fighting guys who were toddlers when we moved in, all they have ever known is us occupying their back yard.
Meaning, we are creating more terrorists than we are killing by staying there long term.
If we had something to do, we should have done it and called it quits.
If we needed to rebuild, fine, but that doesn't (shouldn't) take 13 years.