To be fair to Star Trek, the shows generally focus on the people on Starfleet vessels, not the civilians on planets. It's implied that war and poverty on Earth

To be fair to Star Trek, the shows generally focus on the people on Starfleet vessels, not the civilians on planets. It's implied that war and poverty on Earth and other "developed" planets is over and the only conflict is in border regions where the Federation borders hostile civilizations. You may have a point in regard to fashion, however.