The initial episodes were remarkably good—entertaining, clever, and genuinely funny, displaying a level of wit that set it apart. It was something you looked forward to watching! However, around season 4, the quality noticeably declines. By season 9, it felt like the writing had been taken over by young viewers of the series...it’s become acceptable as simple entertainment while occupied with other tasks. Ultimately, this program began as an exceptional and innovative production, occasionally reaching moments of brilliance, and I eagerly anticipated each installment. Now, I watch when it appears on a streaming platform, and there are occasional good episodes, but it's no longer worth rearranging your schedule to endure the weaker installments and storylines in order to find the worthwhile ones. It remains enjoyable, certainly, though now it’s more appropriate as background entertainment while working than something you’re excited to watch each week. The show has become a fairly ordinary sitcom that has been simplified for a wider audience. I suspect the series will probably conclude with Penny and Sheldon having a child, which seems like the kind of story often imagined by young fans.

Source on TMDB