As far as why he’s still alive: who knows! We don’t know the direction the story will take yet. He might have more narrative use. Wouldn’t mind a break from Vox next season tho. Give me the cosmic baddies I know are coming!

Vox’s power correlates with public approval/ratings. Alastor needed Vox to aura farm to get him strong enough to break his deal. Alastor pushed Vox back out into the public in every scene they were in to keep him growing stronger, knowing Vox would crash out and lose it all.