Or an unlocked Nexus 4 at $349...
Yes
So for costing 65% more, is the S4 a 65% better phone over the N4 ? I would not say so, yes the Galaxy S4 is a better phone than the Nexus 4, no doubt, but spec wise is not that much better, maybe a 1/3rd better phone in my opinion. Based on these noob simple calculations the S4 should cost like $465
But then we are not factoring in the Nexus-Five, which will be the Nexus equivalent to the S4, the N5 should have equal, or most likely better specs than the S4, and still only cost like $349/$399.
Look at this way, last year in 2012, would you rather pay $649 for the Galaxy S3, or $349 for the Nexus 4 ? I will take the N4 all day long over the S3. Not just due to pricing, but the N4 is just a better phone, not by much, but still little better in my opinion.
So in 2013, would you rather have the S4 @ $579, or the Nexus-Five which most likely won't be over $400.
The Nexus phones are cheaper, plus guaranteed to be first with the newest Android OS right away. Sure I know the Nexus phones seems to skimp out on some things to keep costs down, lately being cheap cameras, and not the best batteries. But I would surprised if the Nexus-Five doesn't have a better camera over the N4, and larger battery this time. Also would guess the Nexus-Five will have a 32gb option, and shocked if it doesn't include an LTE version.