Cosby certainly wasn't the first show with black people in it. There were shows like the Jeffersons, Good Times, and What's Happening. The big thing, though, is that the Huxtable family of the Cosby show were portrayed as a middle class family that didn't feel surprised or out of place to be middle class or upper middle class. And nobody in the show's universe was surprised to see them there.
With the other shows, it still had the inner sense communicated that black people were poor, and black people with wealth... well that was something "special". Cosby had the good economic situation and a strong family, and it was totally taken for granted as a normal thing. And it was a mainstream show instead of a niche show.
Re: Getting over fears.
Cosby certainly wasn't the first show with black people in it. There were shows like the Jeffersons, Good Times, and What's Happening. The big thing, though, is that the Huxtable family of the Cosby show were portrayed as a middle class family that didn't feel surprised or out of place to be middle class or upper middle class. And nobody in the show's universe was surprised to see them there.
With the other shows, it still had the inner sense communicated that black people were poor, and black people with wealth... well that was something "special". Cosby had the good economic situation and a strong family, and it was totally taken for granted as a normal thing. And it was a mainstream show instead of a niche show.