McKenna Grace's Paige Swanson doesn't show up on "The Big Bang Theory." The character debuted on "Young Sheldon" after the flagship show aired its final episode, so her absence is completely understandable. However, Sheldon Cooper's (Iain Armitage) intellectual rival (and first crush) is a big part of his childhood, and it's strange that that she doesn't show up in the final season for one last hurrah. Unfortunately, bringing Grace back into the fold wasn't possible at the time, and the creators of "Young Sheldon" didn't have any more plans for the character.
While speaking to TVLine, co-showrunner Steve Holland revealed that Grace was busy with her movie commitments when "Young Sheldon's" seventh and final season entered production. As such, her services were difficult to acquire, but Holland is happy with the way her story panned out. In his own words:
"When we got into this season, especially with it being a shortened season, we never thought that [Paige's storyline] was an arc that needed more closing than it got. There was a parallel; she was a bit of a mirror image of Sheldon -- a different way that Sheldon could have turned out -- and I think we saw that play out."
While Paige's arc is given a structured beginning, middle, and end, some "Young Sheldon" fans worried about her fate after the series concluded. A cameo in the final season could have eased those concerns, as her last appearance sees her get arrested for stealing a truck.