AnalyzeThis: Actually, a few things happenned.
In the conventional 1. e4 c6 2. d4 d5 3. exd5 cxd5 4. Bc3 Nc6 5. c3 Nf6 6. Bf4 Bg4 setup, black achieves an active posting for his knight on c6 right away and develops his c8 bishop, which is one of the goals of the Caro-Kann in the first place.
Fischer reasoned, I believe, that the placement of the knight on d7, and would block the bishop, if he invested a tempo in moving that pawn from d3 to d4. We see how in the game how black invested tempos of his own to put a knight on e7 and then c6. Also, the presence of the queen on c7 didn't necessarily do anything wonderful for black's game either - mabye it was a little early to develop that queen.
I'm sure that white doesn't win by force but Fischer gave his opponent original problems to solve, and confused him, which is a worthy result of his original play.
The same thing happens in the Ruy Lopez - sometimes white plays d3 instead of d4 right away, hoping to find a more opportune time to play d4.
By the way, the KIA makes excellent sense against the Caro-Kann - the lines that scare you with white are the ones where black goes "all in" with queenside counterplay, ...c5 being a star move. Restained play on the queenside by black means white just gets a free hand to attack.