My question is this: would the smartphone be nearly as popular without the iPhone?

Apple changed the landscape of the smartphone platform when they introduced the iPhone and suddenly Palm and Blackberry looked stale and Windows Phone looked downright slow. Apple made the smartphone desirable to the masses, especially to those who had otherwise shied away from the monthly costs associated with a Blackberry or a Treo.

Is Verizon Single-handedly Responsible For Androids Success? - TmoNews - Unofficial T-Mobile Blog