Consider for contrast. . .
“In America, you can always find a party. In Russia, the party finds you.”
Each statement make sense and is not funny, but the juxtaposition of the two meanings of “finding a party” and “party finding you” and the differences between the countries that it highlights make it a good joke.
But, to say “for whites, the sky is the limit but for blacks, the limit is the sky,” is a bad joke, and I’m not sure it really makes sense at all.
The two main parts are “the sky is the limit” and “the limit is the sky”. Now, we’re all used to hearing the first one, but the second one, unlike the Yakov Smirnov line, doesn’t make a joke.
Really, since they’re both equating sky and limit with “is”, they really do mean the same thing, unlike the Yakov joke where “to find” is the verb instead of “is”.
If I were to say to you, “if you graduate from Yale, then the limit is the sky,” you would take it to mean the exact same thing as “the sky is the limit”.
Only from your own knowledge of Chris Rock’s angle do you take the unknown phrase “the limit is the sky” and assign it one of the meanings that TellMeI’mNotCrazy mentioned. But, you need to already know Rock’s point to get it.
If I told you “In Made Up Land, for the Foobies, the limit is the sky, but for the Beefoo’s the sky is the limit” you really don’t have a clue about who is better off. You wouldn’t even know one of them was better off if the word “but” wasn’t in there.
I’m a CR fan, but this is a bad joke, and none of your explanations make it a well-written joke, nor (especially) a funny joke.
It’s not like Kennedy’s famous line either. If Kennedy had said, “ask not what your country can do for you, but what can be done for you by your country,” then it would be the same thing.
Are people really arguing over multiple posts about diversity of the alien races in Star Trek or am I imagining that?