With the old queen who had disappeared and the new queen resigned her job only minutes after being crowned, the vampiric race was left without a ruler. They would have been on their own with authority. A manner they were used to by then. They had done it for thousands of years already so Rarity couldn't be bothered with it. Out of her own experience were the only times she and the queen met was when she was summoned to come. But there were other effect that were unseen by the unicorn.