This lore was written as an end game for void mages, not some other being. As it currently stands mages can't progress without choosing a path of light and dark, this is meant to provide a middle route.
And yes, you still can be a simple wizard. Transcendents are simply one way a void mage can go; boons with cost. And you can only progress through change, otherwise you simply stay flat at the current state. Which is not a good one.