Can you work on an iPad like Tim Cook?

In a recent speech celebrating a new partnership between his company and IBM (IBM), Apple (AAPL) CEO Tim Cook asserted that he did about 80 percent of his work on an iPad, and suggested that this should work for everyone else as well: "There's no reason why everyone shouldn't be like that," he said.

That's easy for Apple's chief executive to say. But how realistic is it for ordinary workers to rely largely on a tablet for their computing needs?Actually, he might not be that far off the mark.

Studies show that 28 percent workers' time is occupied with email correspondence, and the iPad (along with all other major tablet platforms, including Android and Windows 8) can handle most email just fine, including POP, IMAP and Microsoft Exchange.

The most common business suite is still Microsoft Office, and until recently this is where the iPad was at a significant disadvantage, relying on Google Docs and various third-party office tools to replicate Office. Now, full-featured versions of Word, Excel and PowerPoint are available in the iTunes Store for free. You can use these apps to read content for free, but editing requires a subscription to one of the various Office 365 plans.

Of course, the iPad (and other tablets) can handle routine Web browsing, along with specialized apps for social media and business tools for travel, reference, news and more. So can tablets do it all?

Probably not. The biggest hole in any tablet's desktop replacement strategy is traditional business apps. Most industries rely on specialized programs that are fragile and customized, likely working only with certain versions of an operating system (such as Windows XP). The effort to make such tools work on a tablet like the iPad is considerable, and not something many businesses have stepped up to do.

And then there's a simple matter of ergonomics and productivity. The iPad comes with no physical keyboard, for example, and most peripheral keyboards don't have nearly the same feel as a full-size traditional desktop keyboard. Users might not mind using the on-screen keyboard or external keyboard for sending short messages or taking notes in a meeting, but working for hours at a time on more complex projects can be quite fatiguing.

And that doesn't even consider the screen experience; many knowledge workers have come to rely on large multiple monitors, which make it easy to pin windows side-by-side for easy reference and multi-tasking. The concept of multiple windows is completely alien to the iPad (and to Android, although Windows 8 tablets have a leg up in this regard).

Cook's 80 percent breakdown might work for executives who only work on a PC with a very light touch, but for most folks in the real world that number seems impractical and unrealistic. That said, computing is indeed getting more mobile every day. In another couple of years, perhaps the iPad will have evolved enough to make the desktop truly obsolete.