When Apple jumpstarted what’s now called the media tablet market with its release of the first iPad in 2010, many in the tech industry -- including yours truly -- were underwhelmed, decrying it as a big iPod Touch, as well as a bald-faced cash grab aimed at extending the market for Apple’s ecosystem services. Today, with tens of millions of iPads sold, it’s pretty clear that Apple’s contention that the iPad is in a whole new product category is in fact correct. And this past week, we got an indication about how big it’s going to get.

According to the market researchers at Gartner, hardware makers will sell 118 million tablets in 2012 and more than 180 million in 2013. By 2016, Gartner says, almost 370 million tablets will be sold.

That last number is interesting to me because it’s roughly the same as the number of PCs that are currently sold each year. In fact, it’s a bit higher. So if nothing else changes, tablet sales will essentially surpass those of PCs by 2016, assuming Gartner is correct.

Of course, everything is already changing.

I would imagine that the success of tablets will come largely at the expense of PCs. And that many users will decide that a PC is too complex, too insecure, too unreliable, and too powerful for their needs. And that a tablet running a simple mobile OS such as iOS (iPad) or Android will fulfill their needs quite nicely.

This isn’t blind supposition. The simple truth is that most people have been funneling simplistic activities through a horribly complex device for decades now. Checking email, browsing the web, and checking services such as Facebook don’t require a PC. It’s like using a tank to kill a fly.

Some users, of course, will always require PCs. These people, like me, create content, need to type for hours at a time, or perform other more complex tasks. But the percentage of people with such needs, overall, is small. And I think the market shift from PCs to tablets will reflect that. (By 2016, according to Gartner. But I bet it's sooner.)

Of course, Microsoft is racing to market with Windows 8, which will come in two variants, both of which will in some way target the iPad and the Android clones. There’s WOA, or Windows On ARM, the version aimed at ARM-based, iPad-like tablets. And then of course traditional x86/x64 versions of Windows 8 that will run on traditional PCs as well as Intel-type tablets but offer complete backward compatibility with today’s Windows applications. Surely, you think, Windows 8 will make some kind of dent in this new computing future.

Surely. But not, perhaps, the type of dent you were imagining.

According to Gartner, Windows 8 will account for just 4.15 percent of tablet sales in 2012, or just 4.9 million units. That’s understandable, given that Windows 8 won’t ship until September or October at the earliest. But according to Gartner, Windows 8 will never amount to a huge part of the tablet market: 8.5 percent in 2013, and 12 percent in 2016.

During this same time period, Apple’s iPad will race from 40 million units in 2011 (almost 70 percent of the market) to 170 million units in 2016 (about 46 percent of the market). Android, meanwhile, only gains share, jumping from 17 million units last year (28 percent) to 138 million in 2016 (37 percent).

When you factor in actual PC sales, things probably aren’t so horrible. Windows, after all, accounts for the lion’s share of PC sales: 90 percent or more. But Gartner doesn’t address this change, at least not yet. So now we’re going to have to do a bit of supposition.

Let’s say nothing changes. Suppose tablet sales simply halt PC growth entirely but don’t cause a sales drop-off. This isn’t entirely unreasonable. Assuming roughly 350 million PCs sold, 90 percent of which are running Windows, total Windows 8 sales -- PCs plus tablets -- in 2016 will be about 355 million units, compared with 170 million for iPad and 138 million for Android. This is the best-case scenario for Microsoft, and it doesn’t account for the fact that Apple’s OS X will likely raise its share as well.

But what if things go horribly wrong for Microsoft? What if PC sales drop by one third in this time frame? At this point, we see the far more heterogeneous future I’m personally imagining, with Windows selling a combined 245 million units, compared with 170 million for iPad and 138 million for Android. That’s not quite a three-way tie, but it’s most certainly a three-way market where anything and everything is up for grabs.

If we evolve to this market as I expect, things are going to change. And not just for consumers, but for businesses as well. Given this mix of device types and platforms, our manageability needs will change dramatically. User expectations will change dramatically. And Microsoft’s role in our computing infrastructures will change dramatically.

It’s scary, but exciting. And it must be keeping Microsoft collectively awake at night as the company races to complete Windows 8. But it’s something you should be considering as well. It’s likely that anyone who supports technology for a living is going to be expanding their tool kits quite a bit in the years ahead.

Note: Any math errors herein are my own and are not intentional. As Barbie noted, “Math is hard.”