Leonard (Johnny Galecki) and Penny's (Kaley Cuoco) biggest storyline issue would've been solved if the show had ended with season 13. CBS' high-rated sitcom wrapped up in 2019 after 12 successful years. While the show was able to come up with an emotionally satisfying finale, there are certain aspects of it that were divisive, including the revelation that the Hofstadters were expecting their first child.
's original romantic pairing had a tumultuous dating history. , broke up, saw each other, and ultimately got back together for good. After tying the knot twice, their collective arc stagnated as the show started focusing on other characters, particularly Sheldon (Jim Parson) and his own relationship woes with Amy (Mayim Bialik). In fact, the sitcom even tackled this issue with a meta-episode where the pair realized that while their friends' lives were moving forward, nothing was happening to them.
In a last-ditch effort to fix this issue, 's season 12 unexpectedly introduced a problem: apparently, Leonard and Penny had conflicting thoughts about having kids. He wanted children, but she wasn't keen on the idea, especially since she was just starting to establish herself in the pharmaceutical industry. It became their whole story in the sitcom's final season until it was surprisingly revealed in the two-part that Penny was pregnant, and that she is, for some reason, okay with it. This garnered varying opinions from fans, as she was adamant about not having kids. The core issue, however, wasn't that she supposedly changed her mind, but that the series rushed this revelation to the point that it felt unearned and forced. Had season 13 happened, CBS could've properly addressed the plot line and gradually shown that Penny was becoming open to the idea of having children.
By season 13, Sheldon and Amy would've already won the Nobel Prize in Physics, which season 12 spent way too much time on. While the plot line was important, especially since it was about Sheldon's lifelong dream, the sitcom's final outing was so fixated on it that the rest of the characters were practically relegated to supporting players. In fact, was the only other significant narrative during that year. The show dwelled too long on the pair's differences instead of showing that they were actively trying to reconcile their differences. There wasn't any indication that Penny was willing to change her stance on the matter, which makes their seemingly happy ending quite off-putting for some. Raj (Kunal Nayyar) did start dating what would've been his wife through an arranged marriage in Anu (Rati Gupta), but even that arc ended abruptly.
Although ended on a happy note for Penny and Leonard, the fact that their pregnancy was accidental could be an indication of an unhappy marriage down the road. As mentioned, there was no indication that she was mellowing in on the idea of having kids. There's a chance that she could ultimately realize that she still doesn't want to have children, which could make .
Given that the show was still incredibly popular and that certain storylines obviously didn't have time to wrap up properly, it's natural to question why season 13 never happened. In reality, the series wasn't canceled, but star Jim Parsons, who plays Sheldon, didn't want to renew his contract for more episodes. The show technically could have continued without him, but since Sheldon is such an integral part of the series' storylines and core cast dynamic, the showrunners determined that concluding the whole series on a less-than-perfect note was the better option. It may have left Penny and Leonard's arc unsatisfying, but at least didn't spin needlessly on after having lost what made it so special.
