Not really.. if apple wanted to sell more 64 phones they would have not made the 16 model to begin with.
I think the 16gig model is there so they can say "starts at $199" or whatever the lowest possible price is.
You've never been in sales have you? I can tell. I've been in sales for....let's just say far more than 15 years, and I can tell you first hand that leader pieces are designed to entice the customer to spend more money on the higher model or if they get the leader piece the customer will get nickeled and dime'd for the extras in order to enhance the experience. Case in point Apple's cloud storage options. If they can't get the customer to go for the 64GB, the customer is liable to pay for the cloud storage when they realize 16GB is not enough to store a pea in.