Young Sheldon has always had a pre-determined end thanks to The Big Bang Theory's established continuity. Given its prequel nature, its events are expected to run up until only Sheldon's move to Pasadena to begin his stint at Caltech. Because of his intellect, the socially-awkward genius finishes college fairly early, paving the way for him to begin his post-graduate in California where he stays until he gets married to Amy and wins the Nobel Prize in Physics. The Big Bang Theory established that Sheldon starts his master's studies at 14, which means that he only has one more year left at East Texas Tech and Medford in general.
There are rumblings that Young Sheldon season 7 will mark the end of the series. Despite the show's popularity, currently being TV's number 1 comedy, its timeline is gradually approaching Sheldon's big move to Pasadena. So even if CBS is interested in keeping it on the air for far longer, the writers have very little choice when it comes to continuing the show as it is without further damaging The Big Bang Theory's continuity. The network has already stretched out the show's premise for a few years now, evidenced by slowing down Sheldon and Missy's aging. Unfortunately, they can no longer do that, considering how much the actors have grown.
Moving the show beyond Young Sheldon season 7 without making changes is nearly impossible. CBS maintains that it still shares the same universe as The Big Bang Theory, so unless it wants to break continuity beyond repair, it's imperative that Sheldon moves to Pasadena after his final year at East Texas Tech. Luckily, there's still a way for the series to move forward — if it's willing to fully outgrow its titular character. Sheldon may be its headliner, but it has essentially become an ensemble series in recent years, effectively outgrowing its original premise. This means that almost every member of the Cooper clan has been given their respective arcs.
If CBS embraces its true form as a family comedy called The Coopers, Missy and Georgie can spearhead the project as Sheldon relocates out of Texas. If anything Young Sheldon season 6 proves that the series is already in dire need of some tweaks as it makes Sheldon more annoying than ever. Since he spends most of his time at East Texas Tech, he often feels out of place in the grand scheme of things. So Georgie and Mandy don't have the same The Big Bang Theory ties that Sheldon has, CBS has done a good enough job crafting their compelling narratives, positioning them to be Young Sheldon's next leads.
Because of Sheldon's proximity to his siblings in The Big Bang Theory, it was easy to make fun of them. Even Mary made unflattering comments about her other kids for the sake of comedy. As Young Sheldon develops both Georgie and Missy, however, it is becoming increasingly clear that many of Sheldon and his mother's stories are mostly inaccurate. For starters, neither are stupid, they just aren't textbook smart like their gifted brother. Georgie has a knack for entrepreneurship, while Missy is street-smart and witty. While Young Sheldon cannot change the way the pair was described in The Big Bang Theory, the prequel can use those comments to its advantage.
This can be the case with Sheldon's worst Missy story in The Big Bang Theory, where he revealed that she spent 6 years in high school. There's barely any focus on Missy's school life. Young Sheldon season 6 alludes to them, but the show can do so much more to explore this narrative pocket. Missy spending six years in high school means that there won't be any scarcity of stories to tackle if CBS decides to continue Young Sheldon beyond Sheldon's storyline. While Georgie's arc is centered on his path to becoming a successful businessman and devoted father, Missy's plot can be about her growing pains as a teenager.
Because of its prequel nature, Young Sheldon cannot change anything established in The Big Bang Theory unless it contradicts continuity or deems Sheldon a massive liar. So Missy's less-than-ideal future will remain canon. However, the prequel can at least provide context as to how exactly she ended up not reaching her full potential. In Young Sheldon season 6, fans see her struggle with always being overlooked by her parents and how it affects her self-esteem. Her insecurity motivates her to make unsound choices, and it doesn't help that both George and Mary don't do enough to quell her fears about being not enough.
Exploring Missy's arc leading to her The Big Bang Theory debut could help people understand her backstory, which includes how her environment helped shape her future. While Sheldon gets pretty much everything he wants, Missy barely gets any support from her mom and dad. More often than not, she seeks Meemaw or Georgie's help instead of reaching out to her parents. Aside from that, Young Sheldon can also reveal more of her fate post-The Big Bang Theory via adult Sheldon's narration.