David Brin writes:

For the life of me, I cannot picture more than one truly optimistic portrayal of future society in all of TV or film sci-fi. With the sole exception of “Star Trek,” most of the SF we’ve viewed in the last 40 years has been relentlessly critical of perceived technological or social trends. Far from utopian, these films have served us well by dramatizing potential failures. To coin a term, they have been self-preventing prophecies, helping us work out our fears and exploring dark possibilities.

His missive on Tolkien is one of the best articles I have ever read.