Eliezer called the example in the link 95% rigged by virtue of how much the problem was constrained before a program attacked it. Chess is likewise the very definition of a constrained problem.

Certainly, the Kasparov match wasn't "rigged" (other than being able to review Kasparov's previous games while Kasparov couldn't do the same for Deep Blue), but when the search space is so constrained, and tree pruning methods and computer speed only get faster, it's bound to surpass humans eventually. There was no crucial AI insight that had to be overcome to beat Kasparov; if they had failed to notice some good tree-pruning heuristics, it would have just delayed the victory by a few years as computers got faster.