A symbolic thing happened this last June: the world's second largest mobile operating system overtook Wintel machines in unit sales. I'm talking about iOS, the #2 mobile platform behind Android, as noted by venture capitalist Benedict Evans on Twitter:

Symbolic: iOS unit sales are now matching Windows PCs. pic.twitter.com/4qsNg3ntYW — Benedict Evans (@BenedictEvans) July 22, 2015

TMO is an Apple-centric publication, and you may be wondering why the lede isn't that iOS overtook Wintel. It is, after all, kind of a delicious moment of comeuppance. The great Wintel hegemony, the arch enemy of Mac lovers from back in the day, now sells fewer units than Apple sells iPhones, iPads, and iPod touches.

But that's not the story at all. For one thing, Android overtook the Wintel world way back in 2012. The story here is that mobile utterly dwarfs desktop and laptop computing. Civilization has been changing under our very noses, and today even the second largest mobile platform outsells the world of Wintel.

As Mr. Evans noted in the Twitter thread on this topic, "If you think mobile doesn't replace PC as the main computing platform, you're really not paying attention."

That's something. For sure, the developed world still does most productivity, creative, development, and scientific and mathematical work on Macs and PCs. Mobile is still better suited to consumption than creation, but we nevertheless do more and more on our mobile devices.

In the developing world, it's another case altogether. Mobile is computing in many parts of the world. Hundreds of millions of people have only a smartphone, be it Android, iOS, or one of the fringe operating systems like Windows Phone*.

And even more people, billions, have no computing device at all. Most of those who enter the market, however, will do so almost exclusively with mobile devices.

This is a seismic shift in modern life, one that will be best be viewed through the lens of history. Academics will look back on 2015 and its neighboring years as a keystone moment. I don't mean just the passing of the torch from desktop to mobile computing—which we can see with our own eyes—but rather the impact that passing has on societies—rich and poor—around the world.

Many decry this effect. From young(er) people walking down the street with their faces buried in their iPhone, to everyone tuning each other out by listening to their own music through earphones, to people eschewing relationships in the physical world for friendships online.

There are legitimate complaints to be made about those aspects of mobile computing, but only if you hold to the notion that the way we lived from, say, 1976 (the release of Apple I) to 2007 (the release of iPhone) was in some way superior to life before or after.

Or before cell phones. Or before TV. Or Radio. Or the automobile.

Humanity has proven it is robust, and the way we lived before iPhone (or iPod) is no more inherently better or less artificial than any other arbitrary moment in time. Mobile devices are and will change us, and those changes will give way to the effects of whatever replaces today's smartphone.

But that change was cemented this year as the world's second largest mobile platform overtook Wintel in unit sales.

*I kid my friend Windows Phone. You're a legit OS, too.