@walking_carpet:
Yeah, as far as I can tell Lucas and Scorsese are mainly like friends-of-friends. They didn't go to school together or anything since they were at opposite ends of the country, but they both got famous and started making films at the same time, they crossed paths with some frequency, and they had a lot of mutual friends, namely Coppola and Brian DePalma, so they would always be at the same parties and ceremonies. And, of course, Marcia was Scorsese's editor for most of the 70s, which probably cemented any kind of bond more than anything, even if it brought some level of unspoken tension.
But it's more a professional relationship than a personal friendship. Most people Lucas is linked to are like this, Coppola being the one exception. Even with Spielberg, they were never super close, they just work together. It's not like Spielberg ever visits the Ranch just for a beer with Lucas so they can shoot the shit, it's always for a rough-cut-screening or a script meeting or something. I think rather it's just a case of having a circle of trusted colleagues and when you start getting older you start appreciating these people who have been with you in life through all the years and ups and downs, so even though Lucas and Scorsese were never friends and had totally different lifestyles, there is a certain bond there if anything through sheer time. But yeah, I wouldn't say they are particularly close, they just run in the same social circle and have been around each other a long time.