Of course Disney thought Lone Ranger would be a success, production companies will always believe their movies will be a success, publically at least. The Lone Ranger character is a part of popular culture, but it's has really had much relevance recently so it's not surprising that the movie didn't do well. Star Wars is a proven property, and although I know you question it's relevance, it has much more relevance then you probably think it does. I see no scenario where Ep7 earns less the $1b worldwide.
Your original post was making the point that Disney wouldn't announce a Star Wars expansion until they saw the success of the next movie. Even though Avatar hasn't started construction yet, and may not start for a while, Disney has said from the beginning that they wanted to start construction in 2013, so based on this it's obvious that they are not worried about waiting to verify the future success of a franchise before building attractions. As another example look at Carsland. Cars was only a moderate success at the box office and with the critics, especially compared to Pixar's other movies. Despite this Carsland started construction years before Cars 2 came out. They saw no reason to wait then, I see even less of a reason for them to wait to see how Star Wars 7 does.
