FACE IT: MICROSOFT's market dominance-oops, I mean leadership position-is unshakable. The vast majority of today's computers, close to 300 million, run MS-DOS, Windows 3.x or Windows 95. And the bulk of new systems, at least 50 million a year, ship with Win95 preinstalled. At this pace, the year 2000 will dawn on a half billion computers worldwide running MS-DOS or Windows.

Competing operating systems are losing market share as I write this. Even IBM had to concede. Big Blue now officially supports Windows, after having sunk a few billion dollars into OS/2, which many users consider superior to the various Microsoft offerings. Apple, which beat Microsoft to market with a better product, shot itself in the foot by keeping prices high and hardware proprietary. Now the company is too busy trying to survive to pose a threat to Microsoft.

As aresult, the Windows standard is expanding unimpeded throughout the world. Ultimately, that could be the bane of Microsoft's existence, and possibly ours as well.

Windows' dominance is just the latest example of a common phenomenon. The first sufficiently adequate technology usually gains broad acceptance and entrenches itself. Some scuffles over standards may break out initially, but things eventually settle down. Once the solution gains acceptance, the rest of civilization reinforces it-through market forces, legal standards, competitive pressures and economic incentives.

Microsoft's greatest marketing challenge with Windows wasn't competition. It was getting DOS users to upgrade. That didn't begin to happen until Windows 3.0, the fourth release (after Win1.0, Win2.0 and Win386). Even then, the growth in the Win3.x installed base came less from users upgrading than from new computers shipping with Windows preinstalled.

Microsoft has faced the same problems with Win95 and NT. Market acceptance of WinNT took longer than expected, and corporate and home users have been slow to upgrade to Win95. As was the case with Win3.x, Microsoft owes its growth in installed base to new system shipments.

This is the crux of Microsoft's problem: Users are and will remain reluctant to upgrade. And as the legacy base for the OS and its supporting apps grows, the likelihood of a changeover will diminish. The enormous growth of this base over the next few years will suppress Microsoft's desire to introduce any significant OS technology innovations.

To date, Microsoft has managed to sidestep this problem by bundling new OS releases with new systems. But that will yield diminishing returns over the next 10 years as the market becomes saturated with PCs.

By the year 2006, 1 billion to 2 billion computers will be in use worldwide, 95 percent of which will run Windows. The sheer scale of adoption of Microsoft technology will provide tremendous momentum to keep things moving in the same direction. The investment in hardware, software, market standards, training, development expertise, custom applications and deployed environments will make the market resist change, even if it's proposed by Microsoft. The investment in Windows technology will continue to grow each year, feeding the dependence on the status quo.

That's the final irony. Like it or not, Microsoft is stuck with Windows for the long haul. Any attempts to replace its own operating system will cause Microsoft the same problems other competitors would have (except that it won't be battling the market leader). Even if Microsoft introduced a brand-new OS, written totally from scratch, the new platform would have to support so much of Windows' behavior that it would be shackled by its legacy.

As impossible as it seems, Windows may still dominate in 30 years. It may look and work a bit differently, but the principles will remain the same. Our grandchildren will wonder about the quaint relics of terminology and workflow, but they'll see the Windows inheritance in whatever they use. And they'll accept it as part of life, not knowing what better dreams we-and even Microsoft-had for the future.