The iPhone was a runaway success that claimed nearly a third of the market share for smart phones by itself at its peak... even though it was only available on one of the four major carriers. But being limited by AT&T put a ceiling on the phone's reach, and the array of smart phones running Android on all carriers recently surpassed it.

No such restraints will exist for the iPad, which is available in its WiFi-only incarnation without a carrier or service plan at all. Even if competitors can sell their tabs without a carrier (which is not a given looking at the Verizon-pegged Xoom), they will have to compete in a market where nothing stands between consumers and an Apple Store's loving, impeccably designed arms.