Touchscreen was simple hardware it does not make a smartphone any more than a Camera or Internet connection does. There where 3 major gaps, gestures, native apps w/App Store, and a web browser capable enough to run 'Web 2.0' apps. And while not a direct phone feature an internet plan with useful bandwidth caps for regular browsing which also a major jump in how you used them.

Android, Windows phone, and iPhone all added these core features.