In sports, we've watched the great ones retire. Michael Jordan. Wayne Gretzky. Joe Montana. It was tough and their teams were never quite the same, but that's the way the game is played. And so it is in the business world, only executives have longer careers than athletes.Can Steve Jobs be replaced? Apple's got a deep bench with Timothy Cook, Jonathan Ive and Philip Schiller. But there's no way to replace Jobs, not really. That's why fortune tellers speak of dark clouds forming over Apple just like they did when the great salesman, Jack Welch, retired from GE.But let's not go overboard. Apple will continue to be a Silicon Valley star and Wall Street darling without Jobs, at least for a couple of years. Here are three big reasons why:Reason 1: Cook Serves Up SuccessApple shareholders have the most to lose over the loss of Jobs. Apple's stock fell two points after the news of Jobs' medical leave of absence broke, and no doubt will bounce back after Apple reported blowout earnings the next day. The same thing happened when Jobs went on leave nearly two years ago: Apple stock dipped and then reached dizzying heights under Timothy Cook's watch.The news about Jobs revealed that he had been going into Apple's offices only two days a week, meaning Cook was the wizard behind the curtain during Apple's huge quarter. Apple posted $26.74 billion in revenue and $6 billion in profit, including record sales of Macs, iPhones and iPads.From all angles, Cook appears to be extremely sure-footed. So there's no reason to believe he won't make the right moves in Jobs' absence. Even if he falters, Apple won't suffer right away. Unlike sports where the retirement of, say, Peyton Manning probably means the Indianapolis Colts don't make the playoffs, companies are a lot slower to feel the impact of losing a leader. It took the inept John Scully three years to send Apple into the abyss post-Jobs in the 1980s\u2014and Cook is no Scully.Reason 2: Jobs' Work Is DoneJobs' greatness is his ability to deliver game-changing products that resonate with people, and he did that with the iPad. Last year, Jobs said about the iPad: "This will be the most important thing I've ever done." (The iPad vision actually predates the iPhone and, in fact, sparked the iPhone's development.)The iPad is akin to winning a Super Bowl, but no team can win the big one year after year. Apple isn't expected to unveil a game-changing product this year. The focus instead will be on improving existing product lines and continuing to ramp up overseas sales. This can be done without Jobs.Jobs is also known as a tough negotiator, so will Apple miss his deal-making skills? As with the game-changing products, Jobs already completed the big deals. For instance, Apple got the most out of its iPhone exclusivity deal with AT&T and no doubt struck a sweet deal with Verizon. To a lesser degree, the Beatles are finally onboard with iTunes.That's not to say there aren't more high-profile deals to be made, but Jobs has already done the heavy lifting. Today, Apple is the biggest tech company on the planet with a $300 billion market cap, carries a lot of weight with key global component suppliers, and has a $50 billion war chest. Sure, it would be exciting to watch Jobs cut more ridiculously favourable deals for Apple, but it's no longer critical.Reason 3: Ive, the Next Steve Jobs?The loss of Jobs will be felt much further down the road when Apple tries to deliver another game-changing product. This is under the assumption, of course, that Jobs doesn't return. As stated earlier, no one can replace such a visionary and designer, but one man comes close: Jonathan Ive, senior vice president of industrial design."He's arguably the most important person there outside of Steve," Shaw Wu, an analyst at Kaufman Brothers, told the New York Times. "He's responsible for the look and feel of the products, the way they interact with users."Odds are against a company having two great visionaries in a row, but Jobs did have a lot of time to find a worthy successor in the critical area of design. Given the sports theme running through this column, one only needs to look a few miles north from Apple's Cupertino headquarters to be reminded of San Francisco 49ers Steve Young filling in nicely for Joe Montana.The truth behind all the hand-wringing over Jobs, though, doesn't have much to do with Apple's financial future or even its cool products. Like retiring athletes, the loss of Jobs at Apple, perhaps permanently, marks a bygone era and of a legend who left on top with the iPad.These times are always tinged with sadness. Tom Kaneshige covers Apple and Networking for CIO.com. Follow Tom on Twitter @kaneshige. Follow everything from CIO.com on Twitter @CIOonline. Email Tom at firstname.lastname@example.org.