My infatuation with Star Wars is part of my early geek identity. Still a teenager, I was very early to the party -- so to speak. Saw an early screening in San Francisco and used the semi-glossy program from the premiere to show all my friends to round up a group to go see it.
Since Jurassic Park in 1993, computer graphics (CG) make the impossible possible. Sort of. The human brain is so good at picking up subtleties in movement, shadow detail, reflection, color, etc., that even though your conscious mind can be fooled, the subconscious isn't. That subconscious mind is the main tap to our emotions, and if our emotions aren't engaged, our disbelief isn't suspended. The movie doesn't work.
Very few filmmakers seem able to make things look realistic enough to suspend the audiences disbelief enough to get us viscerally involved. You know this feeling more often than not, finding yourself in a near catatonic state as the on screen calamity takes on an increasingly unrealistic sheen that distances, keeping us from caring about what happens next.
Which is why some filmmakers are returning to good old set-building, model-making, animatronics, and other old-school film techniques, alongside computer graphics, to keep today's audiences engaged.
J.J. Abrams is one of the new breed of filmmakers, using the entire cinematic toolbox on Star Trek and Star Trek into Darkness. He's upping the ante on Star Wars: Episode VII, using partly-built full sized props, along with CG to keep us believing. The X-wing in this video from YouTube is partly built, but the engine, wing and struts are CG. I can't tell the difference. At least, not yet. Your mileage may vary.