The largest percentage of Avatar's business has been done outside of the United States. (The number varies as it increases, but as of the 19 Jan BoxOfficeMojo site, it is a ratio of 1.1 billion foriegn to 505 million US.)

Slate's "Explainer" article is essentially correct but misses some emphasis. It would be great if they were to have some videos that show the anecdotes that they wrote about. Having seen the French system in action, and constantly seeing its results, showing it is action is the only way to see why it is more efficient and so effective that one stops thinking that they are speaking dubbed english. (Partly this has to do with the similarity between French and English words, even if the emphasis is different.)

Two other points: One is that the actors who portray the english speaking stars often give an added gravitas to poor acting. The second is glanced at, but should  be amplified: many movies and films need to be dubbed if children are expected to enjoy them, and their countries have laws in place that mandate this - subtitles just won't do.