system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How is it that a season of a show like Game of Thrones can be produced in a year, but a 90 minute movie takes multiple years to film?
gpt
A few things.  

First, a movie doesn't take multiple years to film.  Principal photography is usually done in a couple of months.  The many months after that is editing, CG, composing, etc.  

Game of Thrones has incredible production value for a TV show.  But it's still not "Blockbuster movie" production value.  Until this latest season, large battles were usually skipped for the most part (remember Rob Stark's battle where they just cut to his Mom and then he walked up saying they won?)

The vast majority of Game of Thrones is simply the characters walking through an environment talking each other in an intense manner.  Literally 90% of the show.  That stuff isn't too expensive or time-consuming.