Folks, look at it from Verizon's point of $ view (though it sucks for customers):
Let us assume for easy math Verizon can sell 1,000,000 S4 16gb, but could sell 10% more if they added a 32gb. That would be 1,100,000 total units, but then the current pricing would stand out. They would adjust the prices down accordingly, where if they just sold the 16 (as they are), they could (are) be charging a higher price for a super hot phone and their coverage map to draw people in. If we consider the net gross margin after average customer rebate claim rates, Verizon will make millions more selling just the 16gb, in spite of 10% less. The 32gb weight would have to be a lot bigger than 10% to alter anything.
Long term, it would make more sense to focus more on the extra 100,000 and the mix of new customers in that total, but Verizon is increasing their install base already. Better then to focus more on the device margin instead. AT&T are opposite, since their actual weighted install base is stagnant to declining. For them, it makes more sense to offer the larger model to hopefully draw in more customers for the long term. This is also why they are getting devices like One and the LG Pro. AT&T is bringing in premium devices to draw in and keep premium service customers. They are hungry for customers and Verizon is milking theirs.
Of course, considering Sprint and Tmo's plight, you would think they would do the same thing. Perhaps there is some accuracy that the 32gb available for launch were already allocated.