Cook is an operations person. He makes the logistics work. He's no visionary. Jobs is a visionary, but is not a logistics person. Apple struck lightning when both existed, to provide complimentary ideas and counterbalances.
Same with Ive and Jobs. Ive was a great designer, but no usability expert. Jobs put practical limits on and as soon as Jobs was gone, Ive got total control. The result is some of the least-popular Mac laptops ever.
Lighting doesnt strike twice imho.