If that's the case, why the ritual each time? And why did they go out after Uriel VII died?
However it worked, whenever whoever last lit the Dragonfires died, the Dragonfires went out and White Gold Tower was deactivated. It seems that to reactivate it, a myth-reinforced heir must use the Amulet to relight the Dragonfires. Seems appropriate that the would-be emperor should be the one in control of White Gold Tower.