The most important historical fact you already know

Earlier today while watching TV, a character made a reference to a widely known history fact.  Think you know it?  Quiz time!

Q: Who invented the Cotton Gin?

A: Eli Whitney!!!

You knew this.  I know you knew this.  Everyone knows this.  Once you reach 4th grade, you enter a world where every single American knows who Eli Whitney is and what he invented.  But here's my question:

Why?

Why, of all the people in the world, of all the great inventions ever created, of all the machines that had a huge impact on the course of history, is this fact shoved upon us and drilled into our brains?  I just don't get it.

But I accept it.  And I also accept that I don't really know what a cotton gin looks like.  Or what Eli Whitney looks like.  So I decided to educate myself.

Cotton Gins, what what!

Cotton gins are boxes with a drum inside and a crank on the outside.  They clean seed bits out of cotton so it can be soft and fluffy and awesome for making your clothes.  

Check me out, I invent shiz.

This is Eli Whitney, he of the strange hairline.  He invented the cotton gin and has served as a 4th grade social studies test answer for literally billions of generations.  

I read in Sarah Vowell's Assassination Vacation that Eli Whitney maybe didn't invent the cotton gin all on his own.  I'm not sure if that's true or not because I didn't live back then and I'm not a historian, but I can tell you that her book is funny and I recommend reading it.  

Can anyone enlighten me as to why this one fact is so important for Americans to know?  Does anyone know anything Eli Whitney did?  What was his real job?  Where did he live?  Did he even have any friends?  Answers are appreciated.

Note from me:  Sarah Vowell's book was originally recommended to me by my friend Rebecca.  Rebecca is hilarious and a genius and has good taste in books.  Hence, she deserved a blog shout out for telling me about something totally awesome.