As Snake Plissken said "The more things change, the more they stay the same."
There are basically three reasons for setting a story in the future.
1. Science Fiction Adventure along the lines of Star Trek, Space 1999, Space: Above and Beyond, Voyage to the Bottom of the Sea. These allow the use of futuristic technology in war/exploration scenarios.
2. Time Travel: There are two variants. One, the future is so bad that the heroes must change it (Terminator), or Two, the heroes are part of a future historical event and have influence on it without changing the outcome (The Final Countdown).
3. Allegory: The future has become a repeat of the past just with spaceships and lasers. There is an evil dictatorship that must be fought and defeated or escaped from (Star Wars or Battlestar Galactica).