Image source: Apple.

Do you remember back in 2012 and 2013, when Apple (AAPL -2.19%) shares were experiencing a prolonged pullback that ended up seeing shares decline by 45%? It's a rhetorical question, because how could you forget? (Yes, that was two rhetorical questions in a row.) You might also recall that at the time, investors were calling for Tim Cook's head. There were concerns that Apple had lost its innovative touch, and skeptics wanted to pin the blame on someone.

It's funny how that chorus is silenced when shares are doing well. Besides, the 2012-2013 pullback wasn't entirely based on fundamental deterioration. Last week, Tim Cook celebrated his four-year anniversary on the job, and I'd say he's done a stellar job.

4 charts for 4 years
To start, shares have gained 92% during his first four years. That's after giving some gains back in recent weeks amid all the macro China fears. Sure, Cook gave shares some support on Monday (the day of his anniversary) by emailing Jim Cramer, but you still can't argue with the overall performance.

AAPL Chart

AAPL data by YCharts

Beyond just share performance, Cook has also delivered considerable growth to all of Apple's most important operating metrics. For the following charts, the quarters classified under Cook start with Q4 2011, which was the first full quarter after being named CEO. Naturally, we should start with iPhone unit sales.

Source: SEC filings. Calendar quarters shown.

With Apple shipping nearly 75 million iPhones a couple of quarters ago, it's odd to think that Apple had at most shipped 20.4 million iPhones under Jobs. Expectedly, revenue growth over the same period follows a similar trajectory.

Source: SEC filings. Calendar quarters shown.

Cook also focuses a lot more heavily on the important Greater China market. Steve Jobs had never personally visited The Middle Kingdom, even as it was becoming an increasingly important growth engine to Apple's business. Cook, on the other hand, visits regularly. He was even personally involved in the multi-year negotiations with China Mobile, a partnership that finally materialized in January 2014. You know where this is going.

Source: SEC filings. Calendar quarters shown.

None of this is to say that Cook is a better CEO than Jobs overall. Rather, he thinks different. You could argue that Cook is a more appropriate CEO for what Apple has become. That's especially potent when you consider the shake up that Cook implemented in 2012 in the name of greater collaboration, ousting Scott Forstall in the process. Cook is seemingly a stronger believer in the overlap of hardware, software, and services; increased collaboration goes a long way with navigating those intersections. Jobs had erected numerous internal walls, and tearing down a few of them was a good call.

Plus, the magnitude of Apple's business requires someone with operational prowess, which Cook has. Even though Cook is admittedly not a "product guy," Apple still has new products up its sleeve.

Apple Watch is here. What's next?
Apple Watch will go down in the iHistory books as Apple's first entry into a new product category in the post-Jobs era. It's far too early to say whether or not it's a success, but the new device is symbolic of Apple's ability to innovate without its visionary co-founder.

Beyond Apple Watch, the evidence that Apple is working on a self-driving electric car continues to pile up. Just last week, Apple poached another engineer from a certain electric automaker in Silicon Valley. It's anyone's guess if this rumored Apple Car actually makes it to market, though.

4 more years! 4 more years!
In a way, Tim Cook symbolically represents Apple's maturation. Steve Jobs had noted that Apple had never had an orderly CEO transition in its history. Having a clean succession was important to Jobs, knowing that it would have a lasting impact on the company he brought back from the brink. I wouldn't expect Apple to nearly double in the next four years, and that hefty stock grant that Cook got doesn't fully vest for another 6. Cook is in it for the long haul.