Tim Cook (left) and CEO Steve Jobs remove microphones on a stage at Apple headquarters in Silicon Valley in 2010.REUTERS/Kim WhiteAfter Apple cofounder Steve Jobs died, many questioned whether Tim Cook would succeed.Cook took Apple to new heights, adding more than $3 trillion in market value — way more than Jobs.Cook has absolutely destroyed Silicon Valley's founder myth.Tim Cook is the ultimate non-founder success story. As he steps down as Apple CEO after 15 years, that's the biggest takeaway for me.Silicon Valley lauds founders as the only leaders capable of creating huge, disruptive, and lasting value.

Cook blew this "founder mode" theory out of the water in spectacular fashion.I was there at the start. When Steve Jobs died in 2011, I went to Apple headquarters to report on the scene. Underneath the grief, questions lurked.

Would the company be OK without its legendary cofounder? Cook, a supply chain and operations specialist, was taking over. Would he be able to innovate as Jobs did?Laughing at my pantsThat concern hung over Apple for years.

In late 2013, I rated Cook a "loser" in a USA Today roundup of the tech sector, after he spent most of that year struggling to show how the tech giant could still create blockbuster new gadgets that change the way people live.About six months later, I went to Apple headquarters to interview Cook, Eddy Cue, Dr. Dre, and Jimmy Iovine about Apple's acquisition of Beats.The CEO still hadn't forgiven me for calling him a loser, I think. So when I showed up in a pair of bright green pants, Cook asked if I'd just come from the golf course.

I stammered while Cook and his entourage laughed. Yes, Dr. Dre laughed at my pants. I'll never forget it.Life after SteveThe other thing I'll never forget is how Cook answered one of my questions.

The Beats deal was Apple's biggest acquisition by far at that time. "Would Steve Jobs have done an acquisition like this?" I asked.Cook said he tried not to constantly ask himself "what would Steve do?" — while still running Apple with the same ethos of obsessive product excellence.At the time, I was a little disappointed by the answer.

But over time, I've come to appreciate the nuanced, balanced, and practical approach. Jobs wasn't coming back. Cook wasn't Jobs and never could be.

So the new CEO was charting his own path, while keeping the broad goals and ideals of his famous former boss alive.A $1 trillion milestoneBy 2018, Apple's market cap topped $1 trillion, making it the first US public company to reach that milestone. Instead of being a non-founder loser, Cook had added about $650 billion in value, almost twice what Jobs had.I was an editor at Bloomberg at the time, and I reached out to iPod designer Tony Fadell to get his thoughts."Tim and team have done a masterful job of continuing to develop Steve's vision while bringing operational and environmental excellence to every part of Apple's business to achieve their unheard-of scale while continuing to grow unprecedented margins in the consumer electronics business," Fadell told me.$3 trillion moreSince then, Apple has added another $3 trillion in market value.

The iPhone has gone from a cool gadget to the main way most people in America run their lives.Macs have gone from strength to strength, thanks to Apple's in-house chips — a strategy Cook oversaw and executed on with typical precision. My MacBook is still blazing fast, after more than five years of constant use. Incredible.Apple's services business got started in earnest through that Beats deal, which gave the company a music streaming service to rival Spotify.

Now, services generate well over $100 billion in (very profitable) revenue for Apple."Tim Cook scaled Apple into the company it is today. The world-changing scale is very much because of his leadership and focus," said Matt Rogers, a former iPhone designer and cofounder of Nest, told me on Monday.Was Cook as innovative as Apple's cofounder? Maybe not.

The company scrapped a self-driving car project after years of struggles. The Vision Pro was a pricy flop, and there's a big question about whether Apple is behind in AI.However, there are still new wearable gadgets in the works, and Apple has so far avoided the massive capex that other Big Tech companies are throwing at AI. That could turn out to be Cook's final victory.But the market doesn't lie, especially over many years: Apple is the second, or third, most valuable public company in the world — and Tim Cook made that happen.Interestingly, Apple is roughly tied with Google right now, based on market cap.

You know who's been running Google for over a decade? A non-founder called Sundar Pichai.Sign up for BI's Tech Memo newsletter here. Reach out to me via email at abarr@businessinsider.com.Read the original article on Business Insider