The Red Keep (SPOILERS)

Isn't the Iron Throne inside the Red Keep, which is now destroyed, along with King's Landing? Is it not so that the ruler of the Seven Kingdoms is whoever sits on the Iron Throne?

If the Iron Throne is now (presumably) destroyed, doesn't that technically dissolve the Seven Kingdoms? Maybe that's Dany's plan - not to rule the Kingdoms, but to destroy them. That'd be a twist in the tale!