Her contract was not renewed. I haven't ever seen why, if it was her choice or Disney's. I do think the writing on the wall came when she was no longer allowed to give the candy away.
I think it was said that she had to stop giving the candy away because she couldn't wear gloves and didn't have a commercially licensed kitchen.
There were also some stories that it was prohibited because of numbers of irate parents complaining that their children were not picked to receive candy.
I can believe that one...I quit going to watch her because people were so obnoxious about getting picked or not picked.