special effects can not sustain a movie.
It is really hard when you basicly hope EVERYONE dies at the end.
If you're looking to make Citizen Kane or North by Northwest, sure.
If you're looking to make multi-billion dollar, multi-decadal loved series like Star Trek, Star Wars, or Avatar, then you bet it just takes stunning special effects. Plots are kept simple or trite, but the effects and cinematography are so stunning that it builds a legion of followers, across generations.