Dying is easy, Star Wars is hard
Everyone knows George Lucas loves to complain, and Star Wars obviously wasn't an easy movie to make.
Let's see you make it with the technology that was available at the time, in fact, a lot of the tech had to be created to make the movie, much like new technology has to be made whenever James Cameron of Avatar fame shoots a film.
And as we all know, Lucas didn't direct again for twenty years after what he went through with Star Wars because it was so traumatic.
Lucas recently told Vanity Fair, "The first film was really hard. It was painful. It was unpleasant. We never had enough money, and we were always compromising on everything, and it was a difficult experience all the way around."
Much like Coppola with The Godfather, Star Wars has also been a thorn in Lucas's side in that they both wanted to make smaller, experimental movies (like THX 1138, for example) and their biggest successes put them on the blockbuster track. Still, Lucas has had all the time and resources in the world to dedicate to smaller movies if he wants to, and he could have always farmed out Star Wars to other writers and directors, which worked damn well with The Empire Strikes Back.
And it was indeed a tough shoot to make Star Wars, because reinventing the wheel just isn't easy. If you've read Skywalking, the biography of Lucas, you know the stories of him neurotically cutting off little bits and pieces of his hair until the wastebasket was full and furry, and George eventually being hospitalized from stress, after which he'd clearly had enough, and decided to steer the empire behind the scenes.
I often wonder if suffering can equal a great movie. The Godfather, Jaws, and Star Wars were all horrendous experiences for their directors, and they were the films that redefined cinema. And even the most seasoned veterans will tell you making a movie's tough under any circumstances, let alone a big special effects extravaganza like Star Wars.
According Michel Ciment's biography of Stanley Kubrick, he was fond of saying, "Nothing great was ever accomplished without suffering," and I also remember what Spielberg said when making his notorious disaster 1941: "If you're having this much fun making a movie, something must be wrong."