I'm no Apple insider, but my hunch is that 32GB is right in the sweet spot of what most people probably realistically expect to use. So, basically, they could easily give you the 32GB in the baseline model, but they know that if they do that, they'll be leaving a lot of money on the table because there isn't a stark difference for a large percentage of users between 32GB of storage and 64GB. 16GB on the other hand is a different matter.
The fact that so many people are complaining about this is probably a sign that, if that is indeed the reasoning behind the lack of 32GB model, it was a smart choice from a profit perspective.
If you check the pricing, what they've done is lower prices of the expansions $100 over what they were before, but somehow left the base models at 16 GB. Yesterday $600 got you 32GB and an A7 processor, while today gets you 64GB and an A8x.
So the better question is: how is Apple getting away with selling a 16GB option for $500? It's not really that much space, especially when you take the OS and the space necessary to download updates into account.
They always offered updates in 100$ steps, and price wise the 64G is where the 32G would usually be. If they really kept the previous logic, the 16G would have been gone and the lineup would start at 32G, or we'd still start at 16G but the 128G would be 100$ higher than it is now.
That's on this basis that I was thinking, they couldn't get themselves to start the lineup at 32G. I guess it's the same pressures at play as for the 8G iPhones.
I'm no Apple insider, but my hunch is that 32GB is right in the sweet spot of what most people probably realistically expect to use. So, basically, they could easily give you the 32GB in the baseline model, but they know that if they do that, they'll be leaving a lot of money on the table because there isn't a stark difference for a large percentage of users between 32GB of storage and 64GB. 16GB on the other hand is a different matter.
The fact that so many people are complaining about this is probably a sign that, if that is indeed the reasoning behind the lack of 32GB model, it was a smart choice from a profit perspective.