The number of mavics being sold has increased by 1000% compared to this time last year.
That's because it wasn't on the market this time last year.
Of course there are a lot more mavics being sold now: there are simply a lot more mavics out there.
It's simple math.
The number of used units will continue to increase as the number of new units sold increases.
No mystery here.
It has nothing to do with the firmware/updates/issues or any other aspect of the mavic, positive or negative.
Stop with all that common sense , you're starting to confuse people !