John Stamos was the biggest star in Fuller House, so it's interesting he's not one of the main characters on the show. In 2016, Netflix premiered Full House's spin-off sequel which picked up around two decades after its parent show ended. The original cast of characters returned to reprise their respective roles, except for Mary-Kate and Ashley Olsen who played Michelle. This time, however, the focus was on the younger characters, such as D.J. (Candace Cameron-Bure) and Stephanie Tanner (Jodie Sweetin), as well as their eccentric friend Kimmy (Andrea Barber).
Stamos played the part of Jesse Katsopolis for all eight seasons of Full House and an additional five for Fuller House, where he also served as a producer. Despite starring in various other projects over the years, Stamos is mostly associated with the role of Uncle Jesse from the sitcom. As the laid-back parental figure of the Tanner kids, Jesse was always depicted as the cool uncle who balanced out Danny Tanner (Bob Saget). As a fan-favorite, many were excited when it was announced Stamos was reprising his role as Uncle Jesse in Fuller House. However, instead of capitalizing on his popularity, the sequel barely featured him, only bringing him on as a recurring guest instead of one of the main characters.
There are a couple of reasons for this. Firstly, the creatives behind Fuller House opted to focus on the younger characters rather than relying too much on their older counterparts. To make the show still feel familiar, however, the offshoot simply copied the premise of Full House and used D.J., Stephanie, and Kimmy to mirror Danny, Jesse, and Joey (Dave Coulier) from the original show. Given this, it makes sense Stamos, along with Saget, Coulier, and even Lori Loughlin, who played Aunt Becky, only had supporting roles instead.
Secondly, Stamos was busy with other endeavors during Fuller House's run. When work started on the series before it premiered in 2016, he was starring in his own sitcom, Grandfathered, which he produced as well. The same year the spin-off started, he was cast as Dr. Brock Holt in Scream Queens, followed by a stint on Netflix's You, playing Dr. Nicky. Towards the tail end of Fuller House, Stamos nabbed another primary role as Marvyn Korn on Big Shot which streams on Disney+. In fact, it's likely the reason Uncle Jesse wasn't in the final scene of Fuller House is that Stamos was simultaneously filming the young adult/sports show at that time. Given his career opportunities during Fuller House's run, it's not outside the realm of possibility that Stamos deliberately chose to only be a recurring guest star.
Obviously, viewers wanted to see more Uncle Jesse in Fuller House. It would've been nice if he had more interactions with D.J., Stephanie, and the child cast considering how great Stamos is with kids. It also would've given viewers more idea of what Jesse's life was like after Full House ended. But, unfortunately, that wasn't the plan for the spin-off. Perhaps if the Olsens returned and reprised their role as Michelle, Uncle Jesse would've been more involved.