What factors led to Disney retconning Star Wars Legends in favor of the new Disney Canon?

Question

The Star Wars Expanded Universe is the culmination of decades of work with thousands of new characters and a multitude of plotlines, cultures and worlds, and which has been approved by LucasFilm via their holocron database to ensure continuity. With Disney spending some $4.05bn in cash and stock for Lucasfilm, it would appear that the easiest and commercially safest approach would be to simply adapt fan-favorite plotlines from the Expanded Universe to the big screen.

Instead, Disney opted to retcon the Expanded Universe to Legends and create a new trilogy from scratch, even though they did not have a central vision for the three movies of the Disney trilogy and directors were free to decide on the contents of their film according to most news sources including comments JJ Abrams made in an interview.

Particularly interested in any statements by Disney, their executives or industry analysis on this production decision.

Answer 1

Keeping the EU canon would have alienated the intended audience.

While there are a lot of diehard Star Wars fans who love the EU, they are vastly outnumbered by the number of people who have only ever seen the movies.

The EU canon was frankly too big and complex to condense for people who aren't already familiar with it. The Force Awakens was set 30 years after Return of the Jedi. It pretty much had to be unless you want to de-age the original actors significantly. In the EU this period includes at least two separate galactic invasions. That's a lot of context to explain in a 60 second text scroll.

And that's before you start trying to figure out how the story for the movie is going to fit into the timeline. Keeping both die-hard and casual fans happy was going to be impossible.

Answer 2

It's important to remember that Lucas made Star Wars canon up as he went along (major example of that in the movies themselves here). Lucas himself even made things that are no longer canon (and that many would prefer to forget). But the general gist (even before Disney) was that only the movies were actually canon (LucasArts fan relations circa 2001, emphasis mine)

When it comes to absolute canon, the real story of Star Wars, you must turn to the films themselves - and only the films. Even novelizations are interpretations of the film, and while they are largely true to George Lucas' vision (he works quite closely with the novel authors), the method in which they are written does allow for some minor differences. The novelizations are written concurrently with the film's production, so variations in detail do creep in from time to time. Nonetheless, they should be regarded as very accurate depictions of the fictional Star Wars movies.

The further one branches away from the movies, the more interpretation and speculation come into play. LucasBooks works diligently to keep the continuing Star Wars expanded universe cohesive and uniform, but stylistically, there is always room for variation. Not all artists draw Luke Skywalker the same way. Not all writers define the character in the same fashion. The particular attributes of individual media also come into play. A comic book interpretation of an event will likely have less dialogue or different pacing than a novel version. A video game has to take an interactive approach that favors gameplay. So too must card and roleplaying games ascribe certain characteristics to characters and events in order to make them playable.

The analogy is that every piece of published Star Wars fiction is a window into the 'real' Star Wars universe. Some windows are a bit foggier than others. Some are decidedly abstract. But each contains a nugget of truth to them. Like the great Jedi Knight Obi-Wan Kenobi said, 'many of the truths we cling to depend greatly on our point of view.'

(–LucasBooks' Chris Cerasi as quoted by Steve Sansweet's answer to the question "I'm really confused about canon. Is Star Wars Gamer canon? What about the Marvel series? Are they now considered "Infinities?", Ask the Lucasfilm Jedi Council)

So Disney didn't just jump out here with something new. LucasArts didn't consider any of the books hard canon, so Disney was free to explicitly reject them as such.

Answer 3

Apparently, the story and facts in the films and novels was not considered to be in sync. According to the blog:

In the past, there were two camps developing story — cinematic and published entertainment. But they weren’t as in sync as should be. Kennedy wanted them aligned, created the Story Group. They have much more “of a long-term gameplan than ever before.”

and

Shelly Shapiro also works to develop stories with authors, occasionally visiting Lucasfilm. They all work together to make sure “everything falls into place in the right places.”