Refering to the thread topic: I dont think so. Most pessimistic scifi probably has it right. (yeah many "pessimistic" scifi stories end on a high note but really nothing ever ultimately ends happy, right??)
Think about it. Any story set in earths far future is usually pesimistic. There is a reason for that.
Its because our future is most certainly going to be dreadful.
Again think about it:
War
Overpopulation
Long term climate change (ice ages)
Water supply issues
Natural Disaster (vulcanic, weather, external forces outside of earth)
and than ultimately the death of the sun and earth.(which is very far in the future)
ALL of these things will come to pass. So of COURSE scifi will reflect it. The future really isnt that rosy for the earth. No matter how much us humans like to sugar coat things, sweep it under the rug, close our ears....its all going to happen one way or the other. Its a question of when not if.