One could argue that "traditional" AI is also about creating the "illusion" of intelligence. That is what the Turing test is testing -- whether the illusion is sufficiently good to fool the tester into thinking that they're communicating with something intelligent.

The difference is in the degree to which the illusion has to hold up. Game "AI" exist in a limited, artificial world; so they can get away with "simple" algorithms without any learning elements. General AI needs to operate in the real world (even if constrained to a particular domain), where the "rules" are too numerous and complex to program in advance; thus learning is an essential part of "traditional" AI.