The queen has a special power similar to seeing the future but not quite the same. 
In that future, Souma didn't become king, instead, he became the prime minister. The nobles didn't agree with his reforms, and because he was not the king, he couldn't do anything and the king sided with the nobles. He was later exiled with his supporter(Princess Licia) to a territory controlled by one of his supporters(Duke Carmine) but all three of them were killed because of the nobles.
Duke Carmine was informed of this by the previous king. 
Souma was also crowned king because the previous king regretted what happened.