The Munsters

The simultaneous runs of Munsters and Addams Family doomed both to two-season lifespans. Much of the audience became polarized. Munsters fans would not watch Addams Family and vice versa, but if either show had been on without the other it would have attracted almost the full audience of the other.

Either could have become a major, long-running classic. Addams Family had the better chance, being a comedy/social commentary of the type that later became the major hits, All in the Family and The Simpsons. But Munsters also could also have had its seasons in the sun. After scrapping the ill-conceived and twice miscast role of Marilyn, the enormous talent and charisma of Fred Gwynne and his chemistry with Al Lewis (good friends off-camera, too) could have carried that show for many years.