Why must every science fiction movie turn into a zombie or monster movie

I am going through all of the Science Fiction Movies on Netflix and almost every single one of them involves is just a Zombie movie in disguise. Every possible plot is available to the science fiction writer and director, but they all chose from a very restricted palette of options.

1. Bug Eyed Monster movies where earthling battle critters from space.
2. Zombie movies where an alien contagion turns humans into drooling but easily dispatched cannon fodder.
3. "What would you do on the last day of earth?" movies.

It's no wonder that there is no great clamor to explore space. All the wonder and majesty that we had of the stars in the 50s and 60s has been reduced to dull, claustrophobic "pick- em_ off one by one" films that could just as easily have an office building, high school or trailer park as a setting.