The only thing that came close to the usability and reliability of an iPhone in 2007 was the Blackberry.
FWIW, I never used the original iPhone for a long period of time, but I did use the iPod Touch, and I did have usability issues with it (not in hindsight). Something simple as blocking ads, for example, it could not do without jailbreaking. I call that a design issue. That Google does such, is to be expected as it is their main source of income. Apple? Not so much. Multitasking was also something to forget about.
Unless you have some kind of argument that actually addresses the premise that the iPhone was successful because it was the easiest smartphone on the market to use and had high discoverability, you're going to keep missing the point by responding with features that you wish it had when it launched.
The only major innovation the iPhone was using, was a capacitive touch UI. iOS wasn't polished, as it lacked many basic features. Yet the UI was good enough and simple to use. Nothing I wrote here above is in contradiction with each other. The only thing you appear to disagree on is the importance of these missing features. If they had these features from the beginning, perhaps Apple would've released too late, and the market would be saturated already (as touchscreen devices were coming to the masses regardless).
None of these things, in any way, take away from how simple the first iPhone was to use. Once again, you missed the point completely.