I would really like to see where those numbers come from because so far I have no reason to believe them. If the EU didn't sell they wouldn't produce stuff to it.
eitherway, my main concern is that since a lot of the events and characters is tied together in the EU. Change one wrong thing and you might effect several storylines. for instance lets say they make the Vong wars uncanon. Well alright they were rather boring anyways. however that would effect the character development of Jacen Solo meaning no Darth Caedus = the 8 Legacy of the Force books are uncanon, ups!
The same thing would happen if they should decide to kill some key character, lets for instance say they kill of Mara Jade before she originally die at the hands of Jacen. Well, first of all Ben Skywalker might not be burn, secondly Jacen would have to sacrifice someone else to become Darth Caedus = story is uncanon.
Then if that happened the Fate of the Jedi novels would also be uncanon since they are affected by the effects in Legacy of the Force etc.
As I said one stupide move might destroy a great many storyline and THEREFORE Disney need to be careful.
However, if they manage to do that there might come much good out of them buying Lucasfilms.
100k copies for a book that is pretty good espeically when you consider how cheap they are to make. There is a reason why who is it Del Ray is the publisher of all the star wars books. Because they sell a consisten amount (around 100k copies per book) and they use it to give new writers or good sci fi writers that want to widen their audience a way to do that.
Here are some actual break downs of the book sales
In Adult Hardcovers:
Star Wars: The Force Unleashed, Sean Williams, 103,232
Star Wars: The Clone Wars by Karen Traviss, 101,146
Star Wars: Legacy of the Force: Invincible, Troy Denning, 101,034
And in New Children’s paperback:
Star Wars: The Clone Wars, Tracey West, 190,700
Star Wars: The Clone Wars: Battle at Teth, Kirsten Mayer, 186,282
Star Wars: The Clone Wars: The New Padawan, Eric Stevens, 152,661
Star Wars: The Clone Wars: Intergalactic Adventure: Activity Book, no author listed, 119,621
Star Wars Fandex, Christopher Cerasi, 103,191
See the consistently sell in the 100k range. Of course it's not anywhere near as much as toys, movies or games but it's a respectable amount.