Change in Writing and Humor: Some fans believe that the show's writing and humor have evolved over time, and the newer episodes may not resonate with them as much as the earlier ones. Comedy is subjective, and what one person finds funny, another might not.
Nostalgia: The first few seasons of SpongeBob SquarePants hold a special place in the hearts of many fans who grew up watching the show. Nostalgia can create a strong emotional connection to the past and make newer episodes seem less enjoyable in comparison.
Character Development: As the show progressed, some fans might feel that the character traits of SpongeBob and other main characters have changed or become more exaggerated, altering the dynamics that originally drew them to the show.
Different Audience: The target audience of the show may have shifted slightly over time. As the creators aim to appeal to new generations of viewers, the humor and themes may have adapted to suit their tastes.
Longevity: SpongeBob SquarePants has been on the air for a very long time (since 1999), and some fans might feel that the show has lost some of its freshness and originality over the years.
It's important to note that while some viewers may feel that the show's humor has changed, others may still find it funny and enjoyable. Humor is subjective, and people's tastes can vary widely. The show's ongoing success is a testament to its enduring popularity and appeal to a broad audience.