Only one they're not really doing is Spiderman and that's because they just Sony ran it into the ground. And they haven't really done "origin" stories per se. Thor wasn't an origins story. He was already Thor. they just showed why he came to Earth. They never did a SHIELD origins story. Falcon, and Scarlett Witch didn't have origin stories.. but they rolled them out in away that made it seamless. Guardians of the Galaxy wasn't an "origins" story. They simply showed why they teamed up. Captain America Ant Man and Iron Man was the only real origin stories.
In all honesty Marvel had to do more because casual fans didn't know about those characters. So they had to roll them out in away that people could become familiar with them and adjust so by the time they dropped The Avengers people wouldn't have to guess who they were. With Black Panther and Doctor Strange, they've already put easter eggs in several movies as well.
DC has the character star power so they don't need origin stories but execution is everything. Look at how they dropped villians in The Amazing Spiderman and Spider Man 3. It's hard to have that many characters in one movie and give them equal screen time. When it's that bloated, its hard to really be engaged in the characters. When you have a movie like Civil War with so many characters, its better to have them already established because some of them wont get as much screen time as the others.