The quality of the episodes without the John Boy character nosedived in Season 6, due to many contrived storylines and the limited acting ability of the rest of the cast portraying the other six Walton children.
Ellen Corby, 'Grandma Walton', suffered a stroke in November 1976 and was not in any further episodes until 1978, and then on an extremely limited basis, and the effects of her stroke greatly impaired her speech. Richard Thomas, 'John Boy', left the series after Season 5.
