There is no Constitutional requirement that the swearing in with the oath be done by the CJ USSC. In fact, there’s no Constitutional requirement that anyone conduct the swearing in with the oath - only that the President take the oath.
The rest is just tradition and ego.
What does an oath mean to a man who is a supposed Constitutional scholar and doesn’t meet Constitutional requirements for the job he is taking.?
Twenty-seven posts in before something rational is said. This place is slipping.