Those sold at 170 could easily sell at 210 now, and that's more than 20% difference.
Of course,
if they had known at $170 that price would soon stabilize at $210, they could have easily waited. But they did not know it, that is the whole point.
Investing is not about
knowing where the price is going. (If you know it, you're a manipulator/controller, not investor.)
Instead of knowing the future, there are
probabilities concerning immediate future price development. Those can be calculated from historical price series, etc. and one of them is that
selling after a large drop is -EV, (ie. stupid).
If you fail to know these probabilities, you are bound to lose, because you make bad trades.
It is quite simple actually. Like Poker, good players know their things. In each hand, if they have only 2% advantage, they beat the house, and consequently, win.
Bad players not only fail to know their stuff, they even fail to acknowledge their existence. Good luck with that, more money for the knowledgeable ones.
Fundamentally I see no reason whatsoever in selling, so the whole debate is painful. In my understanding, Bitcoin is not any weaker, nor its prospects any worse, now, than when it was $300 some days ago. Or perhaps they are, but the difference in EV is
certainly less than the difference in price. Therefore I more likely lean on buying, because
1)
BTC is relatively better than before, vis-a-vis the other components in my portfolio (assuming they haven't changed during the drop), and
2)
BTCs percentage of the portfolio has declined due to the drop.
Sigh.