The decision to route all purchases through a single payment mechanism makes great sense for Apple, which takes 30 percent of all sales, but it has also helped nurture the ecosystem by making it easier for consumers to buy small apps impulsively with one-click ordering. People don’t want to thumb-type credit card information into their phones each time they download a game to distract the kids during a long drive in the car. One-click purchase also supports lightweight, inexpensive apps, the revenue from which can support small software teams.

Consumers are also willing to experiment with new apps because they know that they have been screened for viruses, malware and other stability problems as part of the App Store’s approval process.

The fact that the iPhone platform runs exclusively on Apple hardware helps developers innovate, because it means they have a finite number of hardware configurations to surmount. Developers building apps for, say, Windows Mobile have to create programs that work on hundreds of different devices, each with its own set of hardware features. But a developer who wants to build a game that uses an accelerometer for control, for example, knows that every iPhone OS device in the world contains an accelerometer.

The maniacal attention to detail and usability in Apple’s consumer products also applies to its software development platforms. However much developers might complain about the torturous app approval process or the sharing of revenue, most will tell you that the iPhone development tools are a delight.

Apple took a lot of heat waiting a year after the introduction of the first-generation iPhone to open the App Store. At the time, it contended that it wanted to ensure that the development tools it shipped met its standards. The success of the App Store suggests that this patience was well worth it.

None of which is to suggest that the iPhone/iPad ecosystem couldn’t benefit from a little more openness. Apple should stop blocking apps that compete with the iPhone’s default apps — e-mail clients, for instance — as this is the one area where innovation has truly suffered.

Of course, innovation and democratization are not the only reasons to champion open platforms. Given the current size of the iPhone’s installed base, as well as the projections for the iPad’s adoption, it is troubling that one company can single-handedly veto any new application on a whim.