Why are Apple iPhone Users Slow to Upgrade?

Meredith Vieira writes: "Apple and Google have traded jabs over who’s registering more users, but Android wins the upgrade race—at least when comparing two of the most popular phones, the Apple iPhone 3GS and the Motorola Droid. Two weeks into the upgrade cycle, almost twice as many Droid users had upgraded to Android 2.2 than iPhone 3GS users who upgraded to Apple iOS 4. The reason? iPhone upgrades require connecting your phone to your computer. Which raises another question, will Apple eventually offer over-the-air upgrades to iPhones and (especially) iPads?"