Editroid said:

Is there any Mac software that can allow me to restore and remaster movies in the same way that most studios clean up the video and sound quality for new releases of their movies? In other words, a way to restore the 2006 non-anamorphic Star Wars movies to be close to the quality of the 2004 DVDs?

Studios don't use a VHS or DVD version of a film as the basis for their restoration. The reason restorations can look so much better, is because they are working directly off of a pristine film print. There's only so much improvement that can be done off of a lousy digital master.