I read about a study in Scientific American many years ago regarding this topic, and IIRC the results of the study showed that accepting a loss and reinvesting was what separated the good ones from the others.
The argument as I recall it was that stocks that fell hard seldom recovered, at least on shorter timescales, thus it was almost always better to accept that loss and reinvest whatever is left in something else.
except for a lot of the mega caps today. Look at how much apple fell when they almost bankrupted themselves in the past and had to get steve jobs back.
Look at microsoft, when they almost lost to google (and clawed their way back).
The reason they seldom recover from a low, is that a stock being low is synonymous with the business being in financial trouble. Most businesses in financial trouble don't make it out.
But those who do are ones that managed to get somebody good to turn it around. Of course, as an investor, you can't know who's "good" until after they're done turning it around.
So in the end, those with deep pockets that can weather the lows, would end up with a superior return in the long run.