"Quaint?" Uh...no.
Kept Communism from spreading West while it was in place.
The problems in Germany exemplified by the Berlin Wall...good because they kept W. Germany from being infected? Never heard that one before.
Meanwhile Germany's standard of living is declining relative to the rest of the world.
Exactly right. This goes to show you that America didn't solve all Germany's problems in a fell swoop. Neither will Afganistan's problems be solved quickly. Particularly since they are more backward than Germany was.
Only because we chose not to finish WWII properly. Had we defeated Russia, the Berlin Wall would never have been built, and two+ generations would never have known the tyranny of the USSR. Communism was a Russian problem that we allowed to spread into Germany after the war.