The single biggest announcement that came out of Apple's event today wasn't the iPad Air, the new MacBook Pro, or the next rev of the now-made-in-America Mac Pro -- all of which people could see coming from light years away. It was word that the next version of OS X, named Mavericks, would be available as a free Mac App Store release.

In a presentation riddled with the usual "thinner, faster, lighter, better battery life" news, this stood out as a truly strategic move and a major break from Apple's own tradition.

Word on Mavericks has been positive without being ecstatic, with its biggest attraction its tight interplay with the "Apple app fabric." Was Apple offering it for free because it didn't feel there was enough changed in the OS to warrant a price tag, despite previous updates to OS X (even minimally incremental ones) carrying a cost?

The more likely idea, as Apple itself admitted in its presentation, is to get as many people as possible -- even "complete laggards" still running Snow Leopard -- on the new platform.

Some of this might also be Apple trying to tamp down worry in its user base that the company is turning its back on the desktop and making itself into an all-iOS, all-the-time outfit. The new MacBook Pros and the revamped Mac Pro put the lie to that notion and reinforce the idea that Apple appeals first and foremost to the user willing to spend for quality. But offering the next OS X for free cements the positiona little further.

That move also sends that much more of a warning to Microsoft, which has been offering Windows 8.1 as a free upgrade for Windows 8 users (albeit via a snafu-laden rollout). In fact, Apple is one-upping Microsoft in a way: Windows 8.1 is only free for Windows 8 users, whereas Mavericks is free for users of any version of OS X. It's now also that much more likely any future point revision of OS X will also be a free upgrade, giving people who resisted switching to the Mac for that reason one less thing to hold out on.

Apple's portion of the PC market has never been large, but what Apple's lacked in market share there it's always made up handily in customer devotion and satisfaction. If this is Apple's first step toward making OS X much more of a commodity presence on its hardware, instead of what amounts to a cost-plus add-on for those who want to stay current with it, that's only likely to help.

This story, "Apple's biggest new announcement was the free OS X upgrade," was originally published at InfoWorld.com. Get the first word on what the important tech news really means with the InfoWorld Tech Watch blog. For the latest developments in business technology news, follow InfoWorld.com on Twitter.