I thought the suggestion was more that by producing just one variant for all markets/regions/carriers, Google/LG can leverage economies of scale to bring the overall price down.
I haven't looked at the S3, but past Samsung models have had a bunch of variants marketed under the one model name.
(How much this really factors into the pricing, I doubt if we or Wired can really know.)
Simple, Samsung has to sell there product in an attempt to make a profit on them, Google on the other hand is selling theirs at or near cost as a "Content delivery system". They don't need to make money up front for the device.
Well lets assume they want a markup of 40% for profit, that would bring the cost to 420. The price I am seeing is $550 on amazon. This brings the cost difference at $110, and IMO this could easily be chocked up to R&D and other misc costs.
I haven't looked at the S3, but past Samsung models have had a bunch of variants marketed under the one model name.
(How much this really factors into the pricing, I doubt if we or Wired can really know.)