Essentially, you just said that perhaps 20 million people are aware of whatever this "Thrawn Trilogy" thing is. Compare that with what has to be over 1 billion people worldwide who are familiar with the movies. Almost everyone in developed countries has seen them - in fact, even in places like Russia if you hear a younger person say "I never watched Star Wars" it's shocking.

While the demographic that has been targeted for the Expanded Universe is probably likely to dump out massive amounts of money on merchandise, books, games, etc., even disproportionately to income, it's still a much, much narrower demographic. Even if you double the sales on the trilogy you mentioned you're still under 50 million people, the vast majority of whom are probably in certain targeted markets. In other words, the most generous estimate I could give puts the number of people familiar with the Expanded Universe at perhaps 5% (at most - that's assuming only 1 billion people are familiar with Star Wars when I believe the numbers are higher, and doubling and then some the 20 million sales for the trilogy of books) of fans.