Sort:  

Under his leadership, Apple grew from roughly $350B in market cap to about $4T today — an ~11× increase that generated huge returns for shareholders and created one of the most valuable companies in history

Still, history may single out one decision as his biggest "what if"...

In 2017, amid Tesla's Model 3 production crisis, Elon Musk reportedly reached out to explore Apple buying Tesla. The meeting was declined. At that time Tesla's value was roughly one-tenth of what it later became

Arguably, more than any perceived lapse in innovation, declining that meeting to pursue an acquisition stands as the most consequential mistake of his tenure as Apple's CEO