I think were still a ways out? the first phase only converts 1 in 50 to POS and isnt that atleast a year away?

As for GPU pricing, assuming overall profitability drops drastically (though it would have to drop, and stick to about half the current price) then there would be an influx of Cheap Used GPUS possibly even dropping below MSRP. (Though its unlikely to drop more than ~30% below MSRP because miners will just hold their cards 'incase things improve'