Honestly, I think it may have been about either power management or space more so than cost. The problem with comparing to the Nexus lines is that Google subsidizes those, whereas they do not for other Android devices. The margin you're seeing on the Nexus is probably going all or mostly to ASUS. A more accurate comparison would be to the GPe devices, which are $599 and $649 for approximately the same manufacturing cost.
I am certainly not disagreeing with you there. Just that, based on the rumors, people were expecting Nexus type pricing. And if they had sold it for $100ish on contract, i am assuming that they would still be making a profit, and more in line with mid-range devices. Or sell it off-contract around $400, i am sure that they will make a profit on the Play Store since they are cutting out carrier profits.
Really though, if money is an issue, and you didn't mind doing a bit of work, you can get the s4 new off contract for $450 after gc's and etf from best buy.
The Verizon note 2 was $400 off contract, and the DNA was $300 off contract, based on similar methods/deals previously.
Although, admittedly, not many people are willing to do these methods. I just wanted to point out that it is possible, for those determined.
Sent from my Verizon Samsung Galaxy Note II