If you had to name two of Disney's most prominent franchise's right now, they would be Marvel and Star Wars. The days of Mickey Mouse and his crew being the faces of this corporation are seemingly over, though to be honest, those characters haven't been prominent in a while, outside of Kingdom Hearts. While most of us are expecting Avengers: Endgame to be the moneymaker of 2019, there's a good chance that Star Wars: Episode IX does better than it.
No, it's not just because of the Star Wars name (though you never know, fandom is crazy).
According to Forbes, the major disadvantage of Endgame is that there are a ton of other movies coming out after it that might affect its revenue. While it will probably be number one during its opening weekend the movie will have to contend with Detective Pikachu on May 10. Fans might not want to accept it but the Pokemon franchise is huge and could easily derail some of Endgame's money.
Star Wars: Episode IX on the other hand only has to compete with the next Jumanji movie. Granted, the last Jumanji movie ended up being an unexpected hit and quickly became a solid blockbuster in its own right but it's not big enough to dethrone Star Wars. The Last Jedi, whether you like it or not, made a ton of money, even with the last Jumanji movie opposing it.
Avengers: Endgame comes out on April 26. Star Wars: Episode IX comes out on December 20.