333c's answer is excellent. The other consideration is that "the required victory points" aren't fixed; they are 1 + your opponent's VP. Some boards do have a

333c's answer is excellent. The other consideration is that "the required victory points" aren't fixed; they are 1 + your opponent's VP. Some boards do have a dynamic of "there are roughly X VP we are fighting over; get more than half in the fewest turns". On other boards, if someone were to green too early, they would hopelessly clog up their decks. So players build for as long as possible and gain VP only on the same turn as they can end the game. There's a wide spectrum between these extremes.