Funnily enough, when the iPhone launched, it didn't have a native SDK. With iPhone OS 1, developers were supposed to create web apps. That only got changed with iPhone OS 2.
You are right. Steve Jobs also used the opportunity to destroy Flash. But my point still stands: Most web sites weren't developed with the mobile form-factor in mind until a while later.
https://web.archive.org/web/20070722172208/http://developer....