Because we need Rednecks to kick butt?
Let's not forget that the US nearly spoke German to begin with - Not only because of a large population of German immigrants, but also because of a very close vote between English and German as the national language. Japanese (or other Asian languages) are so difficult to learn to read/write that these languages will never become universal.
Exactly. Terms of trade means that Juan Valdez has to pick a lot of coffee beans in order to buy manufactured, finished (especially high-tech) goods. Though cotton and tobacco are cash crops, it is still raw material, so the South would have become like other third world countries unless they could have industrialized very quickly.
I think the same could be said today of the Red states versus the Blue states. With regard to the future, one wonders about the nation as a whole with manufacturing going off-shore, and an increasing service industry.