8. Cloud computing won't work for everything
AMD and Intel haven't exactly given up developing processors for desktop PCs and laptops, and with good reason. Sure, low-wattage chip designs such as ARM and Intel's Atom have become increasingly powerful, but there's still plenty of demand for multicore chips with high clock speeds. Similarly, new PCs ship with ever more onboard RAM, and multiterabyte hard drives are becoming mainstream. If cloud computing will make the desktop obsolete, why hasn't the PC hardware arms race slowed?
The simple fact is that typical PC users still rely on local horsepower for many of their computing workloads. Consider the ongoing popularity of PC gaming: Even the most network-centric multiplayer online games rely heavily on thick client software to render their graphics. As a result, gamers remain the most avid purchasers of hardware upgrades, and they're sure to look askance at any lightweight "media device" that fails to deliver the goods.
Gamers aren't alone. Any application that pushes a lot of data becomes extremely inefficient when an Internet connection is the bottleneck. From photo editing to 3-D imaging to complex data analysis, there are plenty of tasks that simply work better on a PC. Indeed, even Gartner now advises businesses to use caution when evaluating cloud-based SaaS (software as a service), saying it "will have a role in the future of IT, but not the dominant future that was first thought." If the world's biggest software companies can't get a Web-based office suite right, good luck replacing Photoshop -- and that goes double if you shut out technologies such as Flash and Java, as Apple has done with the iPad.
9. Desktop and mobile operating systems don't mix
Designing a post-PC device is something of a tightrope act. It has to support typical PC use cases, but it can't just be a PC wedged into a funky form factor.
"[Microsoft's] tablet was based on a PC," Steve Jobs told the audience at the D8 Conference. "It had the battery life, the weight, it needed a cursor like a PC. But the minute you throw a stylus out, you have the precision of a finger, you can't use a PC OS. You have to create it from scratch."
But what do you include in a post-PC OS and what do you leave out? Perhaps the most infamous example of a mobile OS that tried to do too much is Windows Mobile, which even Microsoft CEO Steve Ballmer has described as a disappointment. In an effort to regain market share, Microsoft is now readying no fewer than five new operating systems for smartphones and mobile devices. That's sure to confuse consumers, but it underscores the difficulty of coming up with a one-size-fits-all platform for mobile computing.
The larger problem is that when you start from scratch, as Apple has done with the iPad, you force customers to do so, too. Considering that Apple's various incarnations of Mac OS were never able to win significant market share away from Windows, the odds that iOS will succeed this time seem long indeed.