Market valuation alone is not sufficient, percentage of market-share matters too. Under Cook, iPhone market-share grew from 15-18% to 25% in US and an insignificant amount to ~20% globally. As an example for why market-share matters, TSMC's market-share is ~$2T, while Apple's market cap is $3.93T (as of today). Yet TSMC has a market-share of close to 90% for ICs in circulation today.

I'm not a fanboy by any means, just looking at the numbers.