Young Sheldon's engagement and wedding storyline with Mandy and Georgie may lack engagement due to the already known outcome of their divorce in The Big Bang Theory. The show has potential to explore untapped storylines for other characters like Missy, but there is no lingering mystery to explain the breakup between Mandy and Georgie since their relationship has already been shown to be problematic. Young Sheldon season 7 has an opportunity to let the characters of Georgie and Mandy grow by having them realize they are not meant for each other, using The Big Bang Theory's canon to their advantage.
While Mandy and Georgie's engagement and wedding is likely to be a major story throughout Young Sheldon season 7, the Big Bang Theory spinoff will struggle to make this engaging thanks to its inevitable ending. Sometimes, the canon of a television show can inherently limit its storytelling. For example, no matter what happened in the early seasons of Better Call Saul, viewers already knew that Jimmy McGill would eventually become an associate of Breaking Bad's meth-making antiheroes Walter and Jesse. Similarly, The Big Bang Theory's canon set the fates of Young Sheldon's characters in stone before the prequel series began, which could cause problems for the show as it progressed.
In some cases, this was a major issue. George Sr.'s Young Sheldon rivalry with Pastor Rob was rendered a lot sadder for viewers who knew that, within a year of worrying about his wife's potential infidelity, the character would die suddenly. However, in other subplots, Young Sheldon's connection to The Big Bang Theory's established canon is a subtler, more insidious issue. For example, when Georgie began dating the ambitious Mandy, viewers had no way of knowing how long this relationship would last. However, when Mandy proposed to Georgie, and he accepted after his own failed proposal, it became obvious that this is his infamously failed marriage from the earlier show.
Viewers familiar with The Big Bang Theory's older version of Georgie know he became divorced at some point, as he refers to an ex-wife during his appearance on the sitcom. As the audience is already aware that Mandy and Georgie eventually get divorced, their season 7 storyline could become tiresome fast. Georgie and Mandy's engagement, wedding plan, and wedding ceremony all run the risk of feeling redundant since the knowledge that George was divorced in The Big Bang Theory proves their marriage doesn't last. While Young Sheldon could explain Missy's future in season 7, the show can only make Georgie and Mandy's fate sadder since their problems are already self-evident.
Young Sheldon has not yet explained how Missy ended up staying in Texas or why Mary returned to the church after she was publicly shamed by the congregation, so these storylines have untapped potential. However, Young Sheldon seasons 5 and 6 provided plenty of reasons for Mandy and Georgie to break up, so there is no lingering mystery that the series needs to explain. The Big Bang Theory's spinoff already made it clear that Mandy is uncomfortable with the age gap between her and Georgie, that she has different life plans from Georgie, and that the pair constantly get into fights. With so many problems, their divorce is no surprise.
Since Young Sheldon's Mandy and Georgie already have a tumultuous, dramatic relationship, their eventual breakup isn't a shocker. The couple has been trapped in an on-again, off-again cycle for a season and a half now, and continuing this dynamic is unlikely to reveal anything new about them in Young Sheldon season 7. The show changes how viewers see The Big Bang Theory's Mary, but it can't do the same for Mandy and Georgie since they weren't a major presence in The Big Bang Theory. Georgie made a few minor appearances in the series, while his ex-wife was relegated to a throwaway mention in one line of dialogue.
The Big Bang Theory didn't tell viewers anything about Georgie and Mandy's relationship, but this doesn't mean that Young Sheldon season 7 can't flesh out their story. If their wedding and subsequent married life saw the couple continue to struggle throughout the season, they could still realize they are not meant for each other and thus both grow as characters by the finale. Since Mandy and Georgie's divorce is already a foregone conclusion, the spinoff can use this to its advantage by delving into how Georgie and Mandy discovered they weren't right for each other. What they learned from the experience could be their subplot's focus.
When The Big Bang Theory's Howard was first introduced, the character was a sleaze with little substance. However, the addition of Bernadette to the show's cast helped develop his persona into a more rounded, likable character. Similarly, Georgie and Mandy's dysfunction is currently obvious to everyone around them as well as to the viewers. However, since their eventual divorce is no secret, Young Sheldon has an opportunity to let their characters grow by having the pair realize this together. If Young Sheldon season 7 sees Georgie and Mandy work out that they need to break up, then the spinoff could use The Big Bang Theory's canon to its advantage.