And I think that is a limited and misleading definition of power. Power is a very broad word. If I wanted to be equally narrow, I could say: The President appoints Judges, Judges do not appoint Presidents. The President is thus more powerful.
I am absolutely sure any individual could change the world more from the seat of the President than the seat of the Chief Justice. Domestically, internationally, you name it. That's power. That's the power of Caesar and Alexander.
If you define power STRICTLY as the ability to very occasionally have the final say, the courts win, but I don't see how that is a useful definition. I think there are legitimate reasons to argue the courts are more powerful...especially during some other eras...but that's not a very good one to me.
Also, by your definition, the courts were more powerful than the Presidency even during FDR which seems....silly.
It's semantics now. You're certainly right that the courts have the ultimate no.