I haven't observend anything like a consistent approach towards any victory condition yet. And frankly, I think claiming the AI "playing to win" is just a plain lie. If I change something, I should be sure that the result constitutes an improvement. If I am not sure, I should have a fall-back strategy. I haven't paid for something which may or may not at a certain point of time in the far and distant future become better. Then they should have asked us to pay later, too.