There are many categories of “worst”, just as there are many definitions for “survive”. (Screw putting punctuation inside quotation marks—In my opinion, that’s for quotes only.)
Statistically, the best and worst persons are in an ever-spinning cycle of life and death. As for the upper and lower sections of people (based on overall goodness), they probably survive.
Nowadays, it isn’t as imperative to be physically or mentally fit/superior. That is, the “worst” usually end up with the “worst”, due to the fact that the “best” are already taken by other “bests”. I guess this could result in a polarization of survival-related characteristics…