Why are tv spin offs so bad?

Answer 1

Who says they're bad?

Frasier was a spinoff of Cheers and lasted 11 seasons.

The Jeffersons was a spinoff of All in the Familyand lasted 11 seasons.

Good Times was a spinoff of All in the Family and lasted 6 seasons.

Maude was a spinoff of All in the Family and lasted 6 seasons.

Laverne and Shirley was a spinoff of Happy Daysand lasted 8 seasons.

Mork and Mindy was a spinoff of Happy Days and lasted 4 seasons.

Happy Days itself was a spinoff of Love American Style which lasted 11 seasons.

Family Matters was a spinoff of Perfect Strangersand lasted 9 seasons.

The Facts of Life was a spinoff of Different Strokes and lasted 9 seasons.

Mama's Family was a spinoff of The Carol Burnett Show and lasted 6 seasons.

Count Duckula was a spinoff of Danger Mouse and lasted 5 years.

And I'm sure there are more shows that spawned reasonable successful spinoffs.

If the shows were indeed "bad" i.e. of poor quality and people did not watch them, they would not have lasted as long as they did.

While it is true not all spinoffs are successful, "Good" or "Bad" are too subjective of terms, so it's not logical to simply say spinoffs are bad.