Why must almost every movie be over 2 hours long?

I'm about to see a slasher and I couldn't believe it when I read that it was 2 hours of running length and this isn't a one time thing. A lot of movies that were usually of one hour and a half of running time are now 2 hours or more and the more bizarre, they have less character development than a lot of 86 minute movies. Why? Because they throw a lor of exposition into these movies, making them dead ass boring to watch.