Refurbs pop up no matter what, this is mainly because of buyer's remorse and general returns. Many refurbs appear probably thanks to these people on you tube who make "unboxing" videos and speed test comparisons, they can't afford to keep the units either but they like to play with new toys out of the box and feel good about the day.
Refurbs show up because people all over the world are in huge debts and can't afford to pay for any of these latest & greatest in one lump sum, so they rather not get into more debt paying it off with interest over the next 25 years +...