After eight seasons of Little House on the Prairie, the tv show was renamed to Little House: A New Beginning, as the show changed its focus from being about Charles, Caroline and their children to being more focused on the lives of Laura and Almanzo.
The reality is that Charles Landon decided to leave the show after eight seasons, although he stayed on as executive producer, and he did appear as a special guest star in the following season.
However, the ratings were never as strong once Landon officially left the show, and it was eventually cancelled due to low ratings following its 9th season and three special longer length episodes that aired as specials the following year.