It depends on what kind of contract he has. Usually in cases like these, it's about making your star client (i.e. George Lucas) happy. Because if you piss him off, he isn't likely to make future investments into the company, and you don't want a respected filmmaker like him badmouthing you. He also might have friends and allies in the company who make sure things go his way. On the other hand, if the audience demand for a certain product outweighs the benefits of placating the star filmmaker; sadly, few know or care about the original version of Graffiti. The changes are so small anyway that a lot of people may see it as nitpicking.