(FORTUNE Magazine) – As far as the information technology industry was concerned, the 1990s were "The Bill and Andy Show." The kingpins of Wintel not only dictated the bits, bytes, and business models of computing but also grabbed starring roles as techno-visionaries who foretold where digital magic would lead us. Such was their celebrity that they transcended the business world and became cultural icons: Microsoft's Bill Gates morphed from a gawky geek into a gawky geek who is also the world's richest man; Intel's Andy Grove, a brilliant and plucky Hungarian emigre who personified the high-tech version of the American Dream, wound up as Time's Man of the Year in 1997.

But a funny thing has happened since the turn of the millennium. The IT business has in essence become the Internet business. And suddenly Bill and Andy don't seem to matter as much anymore. That's not because Wintel-based PCs are any less crucial to our lives and businesses than before, or because Microsoft and Intel are on the skids. Indeed, more PCs than TVs will be sold this year, ensuring that the companies will remain among the most valuable and profitable enterprises on the planet. Bill can't blame the diminution of influence on his antitrust troubles, either. Nor is it a result of both men's yielding the title of CEO to others in recent years. (Both hung on to the chairman's seat, and Gates now also calls himself Microsoft's "chief software architect.") And it isn't as if the two are trying to swim against the tide of Internet innovation. They're both bigtime believers.

No, the Internet revolution has diminished the stature of Gates and Grove for reasons that are subtler--but are probably powerful enough to prevent other figures from towering over the IT industry anytime soon. For one thing, what we loosely call the Internet is by its very nature viral and all-embracing, already enabling traditional infotech to sprawl into what were once discrete telecommunications and consumer-electronics industries, and vice versa. Gates and Grove attained he-gemony by exploiting a couple of key chokepoints in computer architecture--the operating system and the PC microprocessor. But in the new, more diverse IT world wired together by universal Internet protocols, there are no such obvious chokepoints to commandeer. Nor is the Wintel PC architecture technologically appropriate for many of the digital devices--cell phones, PDAs, network appliances, set-top boxes, and so on--that are now being plugged into the Internet.

Just as significant is the possibility that we no longer need techno-visionaries. The Internet revolution has been a sensational event to behold, grabbing the public's attention like no business phenomenon in memory. It amounted to the final, most wrenching--and yes, most exhilarating--stage of the infotech revolution that began in the 1950s. Before ubiquitous data networks emerged, information technology hadn't qualitatively changed the way we do business to the degree that, say, steam power or electricity or the automobile ultimately had. Sure, we automated accounting and industrial processes and marginalized the role of the secretary, but until the past five years nobody could quantify true, across-the-board productivity gains from IT. Now some experts argue that network-enabled productivity gains, and the virtuous cycles they created, are, as much as anything, responsible for the renewal of the U.S. economy since 1995.

Yes, there's lots of work left to build out the networked economy, but even my 76-year-old mother knows in a general sense how it will play out. As exciting as the past five years have been, the next decade will mainly be one of painting by numbers--realizing the potential of broadband and wireless, beefing up the infrastructure, implementing new, network-based entertainment, information, and commerce services, and otherwise fulfilling what Gates and Grove and other techno-visionaries have already sketched out for us.

So we've reached a stage that isn't so much about vision or proprietary innovation as about execution and competition. In that sense Michael Dell, whose face graces our cover this issue, is a poster boy for the new era. Dell's success building PCs has come from out-executing everybody else in what, thanks to Gates and Grove, is essentially a commodity business. All the other PC makers have aped his every move. But that doesn't mean Dell can influence the widening IT industry, much less the entire economy, the way Gates and Grove have.

The same can be said of other notable IT leaders. Sun Microsystems' Scott McNealy, a self-proclaimed "factory rat," is the first to tell you that he's anything but a visionary, and that Sun's success is just as attributable to paying attention to mundane detail as it is to steady innovation. John Chambers, the CEO of Cisco Systems, is better known for his managerial knack to smoothly absorb acquired companies than for coaxing forth technological breakthroughs or changing how we think about the future. Even Apple Computer CEO Steve Jobs, the guy who first opened our eyes to the notion that ordinary people should actually touch computers, seems to have scaled back his ambitions. He's now focused more on the aesthetics of personal computing than on bringing to market the next big thing. "I'm not a radical," he once told me. No, he's just a perfectionist.

This is not to say that Gates and Grove and the other IT leaders will recede into anonymity. The networked economy will touch us in so many ways that we'll always want to hear from those who are making it all happen. We'll still be curious about what Bill Gates does with his money and what will come of Microsoft's antitrust battle. Andy Grove, who has already written a couple of bestselling management books, will probably get our attention with another tome one of these days. But the voice of the future will be a Greek chorus instead of a buddy act, as Dell, McNealy, Chambers, Jobs, Larry Ellison of Oracle, Steve Case of AOL, Jerry Yang of Yahoo, and Jeff Bezos of Amazon divvy up the visionary chores. And one quick read of that list leads to an obvious conclusion: It will be one dissonant Greek chorus, suited more to cacophony than a simple tune we can all follow.

Leave it to Peter Drucker, the master business-trend spotter of the 20th century, to put it all in perspective. Says he: "This is the third or fourth time in American history when we had all this emphasis on the 'genius CEO.' The last time was in the 1920s, and before that in the 1880s. That always is the sign of a big economic transition. But it isn't going to last, because the transition to the information economy has already happened."

We can thank Bill and Andy for showing us the way.