A beaker full of death wrote:
the public usually found spin-offs to be inferior...
Usually, yes. But let's not forget such spin-offs as
The Andy Griffith Show
Gomer Pyle USMC (a spin-off of a spin-off)
The Bionic Woman
Mork & Mindy
LaVerne & Shirley
Happy Days itself
Jake and the Fatman
Ahh, but there's more:
as the medium--up to that point--had a long stretch of spinoffs which failed to attract the public and/or reach the same level of quality of the parent series.
There's not a single All in the Family
spinoff held in the same high regard (and Good Times
is regarded as very offensive in many ways), and that includes the show it morphed into, Archie Bunker's Place
. Lou Grant
is largely MIA to later generations, while parent series Mary Tyler Moore
still runs and is praised frequently. While not an official spinoff, The Green Hornet
eventually became part of Batman
's official TV continuity, but if you ignore latter day Bruce Lee nostalgia, or memories of the crossover, TGH
did not reach the skyrocketing height of Batman
Then, there's more which failed outright, and/or never approached the success of the parent series:
(a failed spinoff of The Partridge Family
The Girl from U.N.C.L.E.
(a spinoff of Burke's Law
Three's A Crowd
(from Three's Company
was retconned during production to be associated with Diff'rent Strokes
Just the 10 of Us
Day by Day
(spinoff of Duet
Top of the Heap
and Charmed Lives
(Who's the Boss?
spinoffs--both earned quick deaths).
There's more than enough failed or disregarded series over the decades--certainly enough to get that "Captain Sulu" nonsense out of Takei's mind....but when one was as delusioal as he was--thinking his character needs to be elevated to Kirk-like levels--history soared right over his head.