I would second that
You mention sooooo annoying and the first thing I think of is actually the closest example to come to mind of actual cultural and political influence in entertainment: 60s rock stars and their later imitators. I never got it myself, and thought it very shallow to hang on the pronouncements of a damn musician. Expressing noble sentiments in beautiful lyrics didn't make John Lennon a deep thinker, it just made him a skilled lyricist, poet, composer, whatever; but not an intellectual in a true sense nor necessarily wise. But I think Lennon and Bono (oh god, Bono, he's another one) and other superstars did/do manage to sway sentiment, if not necessarily thought.
But Hollywood? Who takes Hollywood seriously except themselves?