The Big Bang Theory: 5 Reasons It Needs To End With Season 12
2. There's Not Much Left To Show
Considering it's been releasing new episodes for over a decade, The Big Bang Theory doesn't have much new content and stories left to show. Yes, there's always the possibility of running previously used storylines with different characters, such as Penny (or even Amy) becoming pregnant. But where's the benefit to that? Fans have already tuned in to see this sort of thing in the past, so why would they choose to sit through it again?
Sitcoms of this nature typically struggle to piece together new and engaging content in their later years, a trait that The Big Bang Theory has slowly started to follow. We've already witnessed a handful of weddings over the years and seen numerous trips to the comic book store that usually revolve around the same sort of purpose. Some fans of the show may like the repetitiveness of the minor arcs but it'll do nothing to help the show in the long-term.
If there does end up being more seasons season 12, some fans may stop watching either in part or altogether just because they're tired of the show still going ahead. It would make much more sense to end the show on a high as opposed to stopping after the majority of the fan base put their eyes on newer shows.