The Key was Safari
Ten years ago the iPhone was announced. The key of the success to me was Safari.
I clearly remember how difficult it was to browse the web on my Nokia E65.
I had to push up/down buttons until the ghost cursor highlighted the link I wanted to visit. Extremely time consuming.
Apps, the App Store, the gold rush, it all came later. Safari was what sold me on the iPhone.
If you are interested in the backstage story there’s a great episode of Debug with Don Melton.