Would this show be any good to millions of viewers if this show was originally about the lives of two successful people Cliff and Clair who are a rich married couple with no children ?

Well...no.

The premise of the series was that the episodes would be based on on Cosby's classic stand-up routines, just like Seinfeld would be several years later. For example, Rudy was supposed to be based on Cosby's childhood friend Rudy (who was also on Fat Albert), but they changed his sex at the last minute. :)

I wonder how the show would have worked out if Rudy was a male on the show instead of a female.