AI researchers are trying to make AI smarter. Game AI can already be easily written to win 100% of games but that's not the point. Gamedevs are trying to make AI more human-like. I'm not sure the two overlap.
Name some games where AI can outsmart (opposite to brute forcing all possible combinations or cheating like infinite resources, near zero reaction level etc.) human. I'm not much of a gamer, but I haven't seen any decent AI yet for games that have more freedom of action than some card or board games (i.e. chess). There's a StarCraft AI challange, you can watch it online(0), but AI is still no match for even an intermediate player.
I haven't seen any decent AI yet for games that have more freedom of action
That's because decent AI is not strong AI - its lifelike AI. Not AI that can beat us, but AI that can outsmart us in a life-like manner. This means that Game AI must be less good that it can be, to keep the illusion of realism/humanity.
Ultimately the goals are different. The goals for academic/industrial AI are intelligent decision making. The goals for game AI is to be fun.
That doesn't mean that its always possible to make an AI that can beat a human player. Many strategy games, as you mentioned, are still too complex. I think "100% of games" doesn't mean "you can already write an AI that can win any game", but rather "there exist many games where the AI can win 100% of the time". Because the former is not true, as you demonstrate.
But the real test of AI is not in speed and accuracy; it's in planning, outsmarting, figuring out the right tactics and strategy. For a game that's mostly about speed and reflexes, or one that's about calculating through a limited number of options, AI can be great. But even the best AI still sucks at complex strategy games with uncertainty and incomplete information.