He is more of a collaborator now, but not when he started. He had to be coerced into collaborating.
I disagree that he is more of a collaborator now. THX was fairly singular, it is true, but Walter Murch was still behind the script and much of the concept, and he had Oliver Hailey do a screenplay draft as well. But the film is so stripped down that it's easy for one person to control the whole thing, it was almost like the world's most expensive student film in some ways. But Graffiti was extremely collaborative, and Star Wars even more so. And of course those were the last films he directed for twenty years. So two out of his three early films were highly collaborative. As a producer, Lucas was always wavering between lenient and controlling depending on the product; I don't think Raiders and Empire Strikes Back are that far apart from Last Crusade, Radioland Murders and Young Indy in terms of his approach, I think the difference is that Lucas had more investment and guiding direction with Raiders and Empire/Jedi, so his delegation is more noteable in this respect, whereas the later products he didn't care as much. But even Jedi was very strictly controlled by him. He had his finger in pie on Jedi more than any other film he has produced since, up to and including Indy 4.
Lucas is a great moviemaker pre-1990. (producing the Indy films and finishing the Trilogy.) Then everything turned south, and the same can be said for Spielberg to be honest. (Last Crusade and Empire of the Sun are the cutoff.) Once again I stress the word moviemaker as opposed to filmmaker when I discuss these two. I admire them and their work has profoundly affected my life, but for all intense and purposes they are great at what they do: making movies
I find this curious, because I think films like Munich, Catch Me if You Can, and The Terminal are some of the best films Spielberg has done; he's a different person now, older, slightly more mature. I don't think he could do Raiders and E.T. when he was fifty, and I can't imagine him ever having the sensitivity to do any of his later works when he was thirty. I'm curious though, do the style/subject matter/tone/etc of his newer films turn you off, as in you probably wouldn't enjoy them if they were directed by someone other than Spielberg, or is it just that the films themselves don't work?