Current Apple products are meticulously, exactingly designed and built, but they’re losing the excitement and expectation of something truly new and original that Jobs brought. That’s the big difference I think a visionary leader can make.
Musk is doing the same thing with electric cars and space. Tesla and SpaceX could survive without him for a time, and since they’re very different industries than consumer electronics, maybe even thrive under a Tim Cook-like operator par excellence. But no guarantee.