You need to take Star Trek and the reality it posits within the context of its time. Star Trek was initially pitched as "Wagon Train to the stars"; think back to the westerns of the 50s/60s and you will see a lot of similarities in narrative structure as well as the idea of roving "law enforcement" wandering around a lawless frontier dispensing "justice." The basic problem is that if technology progresses along a line similar to what the TV shows and movies suggest then there is no way that society will remain in a late-20th century stasis to match the shows/movies.

There is some good "hard" sci-fi out there that you should read if you want some interesting suggestions regarding "what will life look like in X years" and I will let others jump in with some of their favorites (e.g. Vinge, Bear, Stross, etc)