When news broke out that The Big Bang Theory was ending in 2018, it came as a shock to many. The sitcom was still very popular and it was coming off of Sheldon and Amy's wedding in season 10. CBS was forthcoming about wanting to order at least a couple of more seasons of the high-rated comedy. The Big Bang Theory's end was spelled by Jim Parsons' decision to leave the series. Knowing full well that Parsons' Sheldon was the true lead of the series, there was a unanimous decision to end it instead of moving forward with an incomplete cast.
Things are different with Young Sheldon, however. All the main actors have expressed wanting to continue doing the show for the foreseeable future. The fact that it has become more of an ensemble series despite a titular character makes it easier for it to move forward even with potential cast departures. This means that Young Sheldon's main cast is likely going to be intact moving forward. Considering how popular it is, CBS is highly motivated to keep it on the air for as long as possible. However, none of those elements will matter if the writers decide on a story for Young Sheldon season 7 that effectively ends the show.
The biggest driving force behind the idea that Young Sheldon must end with season 7 is its timeline. Because of its prequel nature, the comedy is beholden to the canon that The Big Bang Theory first established. Granted that there are so many plot inconsistencies between the spin-off and its parent show, it cannot escape the fact that Sheldon is approaching the age when he is supposed to finish college, move out of Texas and to Pasadena, California, and start his post-graduate studies at the Caltech. Once he returns from his study abroad in Germany, his final year at East Texas Tech will be the focus of his personal story.
In addition to this, Young Sheldon is also the final guaranteed year for the family comedy. In the middle of its third year in 2021, CBS went ahead and awarded The Big Bang Theory prequel a rare three-year renewal, effectively confirming its run until season 7. Moving beyond that means that everyone involved in the show will have to get back to the negotiating table for brand-new contracts. Considering where Young Sheldon is in the established timeline, there's an argument that it would be better to just end things in season 7 instead of still having to deal with the business side of things.
With so many broadcasting platforms nowadays, cancelation has become the norm. TV shows being able to end on their own terms has become a rarity in recent years. That being said, pulling the plug on Young Sheldon is anything but simple and easy. When it started, the prequel was merely supplementary viewing for those who were looking for more The Big Bang Theory-related content. CBS plucked the most striking member of the Pasadena gang and put it at the center of the prequel. It has significantly evolved since then, however. Young Sheldon is no longer just Sheldon's story, with the rest of the family getting their own arcs.
Given this, it may seem odd that Young Sheldon is ending simply because it is losing a character. So many shows have survived cast departures, and in some instances, it even made them better. Granted that it is the show's headliner, but the project has already become so much bigger than Sheldon. Young Sheldon has become TV's number 1 comedy, posting show-high ratings in season 6. This means that currently, it is at its peak. CBS will understandably be more than willing to order a couple of more seasons solely because of this if they are able to find a way to stretch out its narrative.
However, between Young Sheldon's child actors growing out of their roles and The Big Bang Theory's established canon, it will admittedly be difficult to stretch out the show's narrative beyond season 7. For years, CBS has slowed down the aging process of its younger cast to ensure that the comedy stays on the air for much longer. However, it can no longer do that because Iain Armitage and Raegan Revord are now significantly older than their characters. The only option CBS now has is to either create another spin-off or disregard canon entirely.
The first option is rather straightforward. Young Sheldon follows The Big Bang Theory's continuity by ending season 7 with Sheldon moving to California. Meanwhile, the show is rebranded to become a true ensemble titled The Coopers. The revamped series will primarily follow Missy, Georgie, and the rest of the family as they navigate life in Texas. For the second option, CBS can finally decide to separate Young Sheldon from The Big Bang Theory by setting it in an alternative universe. This way, it can continue with the cast intact in Texas, with Sheldon not needing to move and George not dying.