Legendary investor Peter Lynch once said, "All you need for a lifetime of successful investing is a few big winners, and the pluses from those will overwhelm the minuses from the stocks that don't work out." In hindsight, Tesla (TSLA -2.99%) certainly qualifies as a big winner. The stock has soared more than 2,100% over the last nine years, meaning an initial investment of $50,000 in September 2013 would now be worth $1.1 million.

In August, Tesla generated buzz when it enacted a 3-for-1 stock split, its second stock split in just two years. Of course, splitting a stock has no impact on the value of the underlying business. But two splits spaced so close together does imply significant share price appreciation in a very short period of time, and that can be a signal of a high-quality business.

With that in mind, is this stock still worth buying today?

The highest operating margin in the industry

At a recent shareholder meeting, CEO Elon Musk reminisced about the early days at Tesla, noting that critics said it was dumb to start a car company and "dumb squared" to start an electric car company. Many naysayers doubted that Tesla would ever achieve profitability, and a former Daimler chairman even said the company was a joke compared to the great German carmakers. But I doubt any of its rivals are laughing today.

Over the past decade, Tesla has evolved from pioneer to industry leader. It captured 19% market share in battery electric car sales through the first half of 2022, easily outpacing the runner-up -- Chinese EV maker BYD -- which took 11% market share. Naturally, that translated into strong top-line growth over the past year, as revenue climbed 60% to $67.2 billion. But Tesla achieved a far more impressive feat during that time. It posted an industry-leading operating margin of 16.2%.

That success stems from its relentless pursuit of manufacturing efficiency. For instance, it pays 10% less to build battery packs than the next-closest competitor and 24% less than the industry average, due to its proprietary battery cell technology. And that lead is expected to last through the end of the decade. That is particularly important because battery packs are the most expensive component of an electric car. Additionally, its innovative single-piece casting technique -- meaning the front and rear body of the Model Y are cast as a single piece of metal -- has allowed the company to eliminate hundreds of welding robots, saving time and money.

In short, Tesla -- once seen as a joke -- is now a beacon of manufacturing efficiency, and the company became the most profitable automaker in terms of operating margin. But it still has plenty of disruptive potentials left in the tank. For instance, it will expand into new verticals of the auto industry in the near term, with Semi deliveries scheduled to start this year and Cybertruck deliveries scheduled to start in 2023. Additionally, Musk says Tesla will also solve full self-driving (FSD) this year, noting that the FSD beta software would be released to all North American customers before the end of 2022. Investors should be particularly excited about that -- management has often said that FSD software will be the primary source of profitability for its car business in the long run.

Self-driving cars and autonomous robots

Looking further ahead, Tesla plans to start producing robotaxis in volume in 2024. Those vehicles will serve as a stepping stone to its true endgame: an autonomous ride-hailing service. The company has not provided a definitive timeline for such a service yet, but analysts at ARK Invest say autonomous-riding hailing platforms could make $2 trillion in annual profits by 2030. Tesla -- which has more autonomous driving miles under its belt than any other automaker -- is especially well positioned to be a key player in that industry, and that has big implications for its bottom line. As Tesla evolves into a software and services provider, its operating margins (and profitability) should continue to climb.

Also noteworthy, Tesla teased an autonomous humanoid robot at its AI Day event last year, and Musk recently implied that a prototype of the so-called Optimus bot may be on display at the AI Day event this year, which is scheduled for Sept. 30. The implications of that technology are profound, as autonomous robots could relieve humans of dangerous or undesirable work across a wide range of industries. Some critics still see Optimus as far-fetched, but Musk has said on several occasions that it will eventually be worth more than the car business.

So is the stock worth buying? That depends. Many people don't buy into the bold predictions about self-driving cars and autonomous robots, and many also have an understandably difficult time stomaching the stock's pricey valuation. For context, Tesla's market valuation currently exceeds the next 15 automakers' valuations combined, but the company certainly doesn't generate more revenue than all of those automakers combined.

That said, Tesla has a track record for proving critics wrong, and its capacity for innovation is undeniable. For that reason, I think risk-tolerant investors should seriously consider buying a few shares of this monster growth stock today, though 2,100% returns over the next nine years are highly unlikely.