>I can't recall: when the iPhone came out was there a period of 'flailing' as devs figured out conventions that worked?

When the iPhone came out you couldn't develop apps for it.

There was a period of time when everyone was just using the Apple supplied apps and they laid the groundwork for establishing nearly all the conventions. New conventions have since been established (ie. pull-to-refresh) but the 'tone' was solidly set by Apple.