It's pretty hard to see the iPhone and iPad as anything other than a revolution. Similar to how Windows was a revolution in desktop computing (whether you liked it or not).

"Gaining widespread adoption" was never an area Apple was very good at. They were always good at creating consumer-focused PCs. The initial line of MacBooks and iMacs are good examples of this — minuscule user base compared to Windows, but built to Apple's standards of what a computer should be. Their initial aim for the iPhone was to capture 1% of the market, they hardly expected the success they received.