With hundreds of millions of business PCs still on Windows XP, it may seem a bit presumptuous to start talking about the post-PC future, and whether the businesses that own these PCs should be thinking about a change in direction going forward. But let's turn this on its head: With Windows XP set to expire in less than a month, maybe this conversation is in fact overdue.

To date, each time we've come around to replacing a generation of Windows-based PCs, we've replaced them with a new generation of Windows-based PCs. The nuances have involved whether to downgrade to a previous Windows version or whether we could eke more life out of the current generation of hardware and undergo an often difficult OS and software migration instead.

From here on out, though, the conversation can be—should be—different. In businesses, as with individuals, PCs are no longer the only choice.

Some will argue that PCs are the best choice, of course. And I'm on board with that, for certain classes of users. I've argued in the past that one way Microsoft can adapt to this brave new computing world is to mold Windows specifically around the productivity solutions in which it, and PCs, excel. Make Windows for the "doers," as it were.

Today, Microsoft doesn't have to do anything to Windows to make it more appropriate than its mobile-oriented rivals for content creation: It's already a better and more mature solution. (Windows 8 haters may dispute that notion, but relax. Windows 7 is fully supported through 2020 too.) But that could change as Android and iOS continue to mature. The question is whether non-PCs—often, non-Windows devices—make more sense for some users.

Microsoft has a stake in this game, of course. Although we will no doubt investigate where Microsoft's efforts shine and fall short throughout the months ahead, this week I'd like to just focus on the device types, not the platforms.

I've spent a lot of time trying to figure out what this post-PC world might look like, but a Forrester report from late 2013 is perhaps particularly relevant to this discussion. In it, Forrester claims that tablets will reach an installed base of 905 million users by 2017. When you consider there were just 15 million tablet users in 2010, the growth in that market is amazing, and it puts the installed base of the devices in the same territory as the PC. Tablet sales will reach 381 million units by 2017, Forrester, says, having surpassed those of PCs in 2014 or 2015.

Related: BYOD Checkup: Where We're At

Some of the biggest growth is coming in business, thanks to the BYOD (Bring Your Own Device) movement. Forrester notes, among other things, that "specific classes of workers will be issued tablets," moving their usage beyond executives and traveling salespeople to other roles in companies. That's the audience I'm now considering. And I think what we're going to see will mirror how consumers have moved past PCs in recent years.

That is, if it's 2009 and you're out looking for a way to email, browse the web, make lists, take notes, keep up with friends on Facebook, or play a few random light games, the PC was pretty much your only choice. Flash forward five years, and you have choices. Those choices—which include smartphones, "pure" tablets and, more recently, some hybrid PC designs—are more mobile and more connected than PCs. They're simpler and they're often less expensive. They're more desirable, certainly.

PC diehards will add that they also do less. And that's true. And that's why traditional PCs—or traditional form factor PCs equipped with touch screens—will always play an important role, especially in business. But many users—perhaps even most users, one day—don't need, or rarely need, the additional productivity functionality that a PC brings. And the added complexity of PCs, coupled with management costs, makes things even murkier.

In the workplace of 2009, the corporate-issue laptop was the standard. But today, many users likewise can be productive with web-based email, contacts, and calendar functionality, and perhaps even web-based Microsoft Office solutions for the occasional traditional productivity needs. And if that's true, these same users can perhaps stay connected, and stay productive, with a tablet instead of a PC.

And tablets (like smartphones) are no longer the Wild West, isolated islands of functionality that can't connect to corporate backends. Today's Mobile Device Management (MDM) solutions are mature, full-featured, and secure. They're even inexpensive, and they can integrate with your back-end centralized management infrastructure if you've got such a thing, or work in a standalone mode that will appeal to smaller businesses.

In the long run, tablets are going to reset the discussion for business computing, just like they're doing at home, and for the same basic reasons. Instead of resisting this change, embrace it. And if you're one of the XP holdouts, it's possible that your procrastination may actually pay-off. Perhaps this time around, you'll be able to move to a simple, less expensive platform, one with fewer locally installed applications and associated data. Maybe your next PC. . . will be a tablet.