1. Zeus only got 31 kills on Inferno, that is only 1 map, Overpass was owned by electronic.
2. If s1mple or electronic suddenly stop being so skilled and won't be the best players on the team, NaVi will surely drop in ranking.
On the other hand, if device becomes third best player in the team, Astralis can still easily dominate because of tactical superiority prepared by zonic and gla1ve. dupreeh is just an incredible entry fragger and rifler.
So, IMO, device is being highly overrated because of Astralis' successes.