re: Actors who left Successful TV Shows too early

No one here will care, but Robert Horton left the old western Wagon Train when it was #1 in the ratings.

Robert Horton (r) with Ward Bond on Wagon Train:



Pernell Roberts would follow Horton's lead a few years later, leaving Bonanza when it was #1. But after many years in the wilderness Roberts would eventually get another hit series (Trapper John, MD). Horton never did.