Too good to trade.
You trade down and acquire assets when you're at picks 3-10 for the lotto and you need as many chances to strike gold as possible. Think Kings, Knicks, Nets.
You don't do it when you need one guy who is a sure thing. Regardless of position.
You think if a Lebron or Curry clone was available at the #1 pick and they had the pick, Cleveland or GS would pass on them?