half of the time required you to roi is the correct time frame, because it mean that you can reach roi, with simply reselling it plus have some profit on top of that
i'm sure you cna still sell 1 s7 for about the same price you bought it today, those who bought it 2-3+ months ago, are a bit screwed, but they are also near their roi
The ones with month's ago bought the model with more chips and efficiency, so they will be able to sell for more. But you are right it is not to the extent of price dropping I dont think. And the ones that bought at 230's really kinda are stuck and ROI will be hard if going by BTC and not USD.
But selling is good no matter if it's a few months after or 6 month's. Either way you get extra cash you would not if you sit it on a shelf to collect dust. I suggest everyone sell vs setting on shelf as a collectors item or memento.