One of the reason franchise movies suck is that they are made for a worldwide audience. They have to appeal equally to Americans, Chinese, Indians, and everyone around the world, meaning they must have generic narratives, be primarily focused on action and have all but the most basic character traits [good guy / bad guy] and nuance eliminated.
I found these charts in this article in The Wrap, and thought I’d share. They show the percentages the Fast & Furious and Pirates of the Godawful series make in the US vs in other countries. This is the starting place when you want to know why most big tentpoles are horrible.