There's a difference between an AI happening to win and actually PURSUING a certain type of victory.
Culture is probably the only victory that the AI will aggressively PURSUE. They will ramp up the culture slider and even disband excess units. It does often leave them weak but it sometimes can work and they can be quite good at it. I only think that they started doing this in BTS though...
As for the others, AI's can win most ways except conquest but that's more by stumbling into a win than pursuing it.
Domination: A warmonger may get over the domination limit, but often, despite having the power to crush the other civs, it won't attack them due to good relations.
Diplomatic: Yes an AI may beeline the UN or AP, but it won't intentionally change religions or civics or anything in an attempt to win over extra votes. So this one also can only come down to chance.
Science: Yes the AI is more than capable of building the spaceship, but this will be more as a result of having inevitably discovered all the pre-requisite spaceship techs. So, I wouldn't say that they PURSUE it, it just comes about, this is evidenced by the fact that they'll often discover advanced flight before fusion, hardly a beeline.