Draconians were far more powerful, and the Ylfrish were as well. The Hyllian and the Urgarians are just races that the Supremes either made and lost control, or found and watched their collapse.

And the Equestrians aren't close enough to be that powerful. They are several races, which means that the power would be split up amongst them, and would result in the power being too low for each race in the Equestrians for them to really be considered that powerful.