Does some one know the reason why the Ingallses(ecxept Laura)left after 8th season?

According to Laura in the first episode of the 9th season (Times Are Changing Part 1), it had been a hard winter for everyone and especially for Charles. And in a later episode (Home Again Part 1), Charles explains that he moved the family to the city because he wanted make a secure living financially. That he got tired of not being sure where the money comes from next month. Apparently he made a very wrong decision as the family was falling apart.

The sad reason that the Ingalls left was because there was a sad thing that happened to a lot of farms,but the Ingall's where effected the most. They leave to work in the big city, at a suite factory. The city was called Sleepy Eye in the books. The people of Wallnut Grocve even gave him a new suite! After leaving, a new faimly called the Carters, a man and a wife with two small boys, bought the Ingall's farm! Hope I helped!

as far as the storyline of the show, the ingalls moved to iowa because they could no longer make a living in walnut grove, he was worried he wouldn't be able to supply for his family. As far as the actors in real life, I believe I read somewhere that they had other shows or obligations to fill during that time so Michael landon had to write shows that didn't include the rest of the ingalls family.

Its because a lot of the actors didnt want to act on the show again. I know its sad. Season 9 is my least favorite season because its not like season 1-8. I'm am upset of how season 9 ended because it wasn't even a good ending. Turns out i looked in my basement an there was a special edition with 3 more episode that are movies and 2 interviews and a disc called casting. The last 23 episodes are about Albert dying, Laura's baby gets kidnapped and the destruction of the Walnut Grove. I know the last 3 episodes are depressing but you have to go through it. I cried right when the Wilder's and the other people were blowing up the town. That town meant a lot to me. Even through i watched all 9 seasons and 4 movies in less than 2 years. I have them all on DVD.