One element of the early Treehouse of Horror episodes was a tour through the Springfield Cemetery, which featured witty tombstones emblazoned with various names and jokes. Some of the tombstones featured the names of television shows that had tried to take advantage of the show's success.
As the years went on, it became harder to write for the sequence and as the show's initial creative staff began moving on from The Simpsons, they would inevitably start working on other shows that could get parodied. The producers were afraid that could lead to bruised feelings so they quietly eliminated this element of the show.
