You couldn't even build apps when the iPhone was released. The web was our API, according to Jobs. The homebrew/jailbreak community started up almost immediatel

You couldn't even build apps when the iPhone was released. The web was our API, according to Jobs. The homebrew/jailbreak community started up almost immediately to fill that gap until iOS 2 was beta tested and released with 3rd party app support a year later. So yeah, by the time 3rd party devs were brought onboard, there were lots of devices in people's hands. The trick is to have killer first-party apps, which the web browser and maps very much were on the original iPhone. Nowadays, exclusive killer apps are a bit harder to come by.