Last quarter, Apple made $6.8 billion in sales in "Greater China" — which includes Hong Kong and Taiwan — up 67 percent from the year before.
Sales in the Americas and Europe? Up less than 15 percent.
(Read More: Apple Wobbles as Mobile World's Walls Come Down )
This, in a nutshell, is the challenge that faces the entire mobile industry: Growth opportunities lie in emerging markets, where a new price-sensitive middle class is booming. To win the next phase of the computing race, the heavyweights will have to rethink their approach.
That's also what's weighing on Apple's stock— and it's sure to be a major discussion point at the company's shareholder meeting Wednesday.
(Read More: Samsung's New Phone Will Debut on Apple's Turf )
Investors worry that last quarter's declines in gross margins and earnings growth is a sign of things to come. If Apple has to sell its devices for less money to grow in emerging markets, or risk losing market share to Google, it puts the company's unstoppable image in doubt.
(Read More: Mozilla Aims to Outfox Its Mobile Competitors )
But Google's not exactly in the clear, either. One of the major announcements out of the Mobile World Congress event in Barcelona this week is the debut of Mozilla's Firefox OS for smartphones.
The concept is similar to Google's Chrome OS for PCs: Instead of a traditional operating system, Firefox OS is basically a browser designed to run web apps. The likelihood is that Firefox OS, at least in the early going, will try to challenge Android at the low end of the smartphone market.
Another upcoming mobile OS, Tizen, is similar. With backing from Samsung, Intel and others, Tizen aims to provide a more web-friendly alternative to the strong position iOS and Android have in the smartphone market. Together the two platforms captured more than 90 percent of the smartphone market in the holiday quarter, according to Strategy Analytics.
So what's an investor to make of all of this?
(Read More: Facebook Is Giving Away Free Mobile Data to Some Users )
1. Platform momentum doesn't reverse easily: As exciting as all of these headlines are, there are some important truths to consider. Mainly, it takes a lot to unseat a platform leader — and that's what iOS and Android are right now.
Don't believe me? Think back to Windows Me and Windows Vista. Consumers didn't love either one, but Apple still wasn't able to grab significant market share from Microsoft at the time. What changed things for Apple? An entirely new category of devices and services: the iPod and iTunes. Rather than just take Windows PCs head-on, Apple built a business on top of the PC ecosystem that eventually overwhelmed it.
2.The titans are fumbling around for a new idea: Google is experimenting with a $1,500 display that you wear on your face, and a $1,300 laptop that runs on a browser.
Intel plans to unveil a paid premium cable TV service that requires a broadband connection. Hewlett-Packard is launching a sub-$200 Android tablet that's sure to have a very slim profit margin.
You know what this means? For the first time in four years, the biggest companies in tech are grasping at straws. It's not clear which next big trend will drive consumer purchases.
3. Emerging markets may surprise us: The thing that I haven't seen mentioned much yet is that we in the U.S. don't understand why consumers in emerging markets are buying smartphones and tablets.
That's important because market share in those locations matters only to the extent that it's sticky — where people are choosing a platform they'll stick with for a long time. To the extent that consumers are snapping up Android or iOS phones on prepaid plans and aren't downloading many apps or buying much media, they could very easily switch to something else in a year.
All that makes for an interesting week as the big companies position themselves for the next big wave — whatever that turns out to be.