Exactly. Zach isn't better than the players who are playing ahead of him. He isn't an average NBA player.
Yet.
He's 19. A rookie. One year of college. Didn't even start on his college team. Was injured in Summer League. Anyone who expects Zach to start right now on an NBA basketball team is setting themselves up for disappointment. I doubt anyone does.
The question of whether he therefore should not have been the No. 10 pick is a different question. To some, it's crazy/stupid to "waste" a No. 10 pick on a guy who won't start right away. To others, if he has the potential to be worthy of the pick in a year or two, they are fine with the pick. I don't see any player we could have had instead who would have propelled us into the finals this season. I'm fine with the pick.
To each their own.