On Chief Justices

I don't know much about the U.S. Supreme Court nomination system. It seems to be a real generator of light and noise.

I am curious though, why a Judge who doesn't have a substantial history would be chosen as the Chief Justice.

While I wouldn't doubt that Mr. Roberts has been busy these past years, I have yet to see where this shows up. It appears that some of his handiwork has been covered up by the administration.

Why not have Roberts appointed and choose someone else as Chief Justice?