I'd bet Roberts learned more than you are giving him credit for. Management styles are consistent and learning them is long lasting and becomes inherent to the person taught. Add in, Roberts remained friends with Rehnquist since his clerkship and it would not surprise me that Roberts would run things pretty much the same way Rehnquist did. Of course, there's no way I can prove that, and it would be interesting to hear from some people who have worked for Roberts to get their take on it.
I was trying to give Roberts as much credit as possible for knowing the Rehnquist leadership style.
But when he actually worked for Rehnquist, Rehnquist was an Associate Justice and Burger was the Chief Justice.
Maybe he picked up on Burger's style of running the court. :o