2014 was also a turning point for the MCU because of another movie: "Guardians of the Galaxy."
"Guardians of the Galaxy" came to theaters several months after "Winter Soldier," and contributed to the MCU's new direction into quirky space stuff like "Thor: Ragnarok" and an action-comedy like "Ant-Man."
Without the MCU to back it up, this would've never been made into a movie.
Even the Dan Abnett, the writer of the Guardians of the Galaxy relaunch the films are based on, couldn't believe his work got adapted into a movie of its scale, or at all. The Guardians of the Galaxy are not exactly new in the comics — they've been around since the late 60s. But the team seen in the films (Star-Lord, Gamora, Drax, Rocket, and Groot) made their debut in 2008.
The movie's star, Chris Pratt, was quite a surprising choice as well. He's a movie star now, but just a few years ago, Pratt was known for playing a goofball on the NBC comedy "Parks and Recreation." Pratt's casting, as well as Dave Bautista and the voice actors including Bradley Cooper and Vin Diesel (huge stars who, in any other movie, would be cast as Star-Lord and Drax to get more tickets in the theater), elevated the movie.
The Guardians of the Galaxy gained prominence after the movie came out, and it was really Marvel's first high-risk movie considering they were even less well-known than characters like Thor and Iron Man.
The Guardians are used in the same way in the 2017 sequel. They're funny, they have attitudes, and sometimes they hate each other. This franchise is both light-hearted and laugh-out-loud funny, has a soundtrack from the 70s and 80s, and stars former TV actor Chris Pratt as the unexpected lead. It really made everything that followed possible.