Why is this crap so famous in US?
This is an ok movie, I'm sure that back then its sfx were on par with Avatar (another just ok movie btw). But Americans decided to hold it as a classic for the ages for some reasons I can't quite fathom.
This is almost obscure outside of the US, something that will shock most Americans but that's a fact. Most people in the world know of the Wizard of Oz, as a name, that's about it.
No Dorothy, Toto, Tin Man etc. Nor very popular side icons like munchkins or witches or flying monkeys. All that is not popular knowledge anywhere else. This is not shown every year on tv or whatever, at least not since 1939 :-)
So why do you think Americans keep it as something so special in their tradition?