Salt of the earth

I liked this comment on an older post about sociopaths being just a natural human variant:

This is very encouraging to read. It does seem more logical to see there being an intended role in nature for those considered psychopaths rather than being an aberration or flaw.

I think the statistic I read somewhere was that approximately 4% are psychopaths. This seems to be exactly the proportion of managers you'd need for any group. Those that can make hard or even life and death decisions dispassionately for the preservation of their tribe, corporation, or nation. The fact that those same people tend to be gifted with an easy charm to persuade others and that they naturally migrate to positions of power would seem to reinforce this. What would be perceived as evil by the recipient might be seen as good to the group following the psychopath who subsequently have food to eat for the winter, a surplus of wives to mate with, or more valuable stocks.

The fact that I see myself equating the decimation of a rival tribe with acquiring increased stock value is not lost on me. Humorous to me though in it's own way...

Are sociopaths like salt? Even just a little too much can ruin a dish, but if you don't have any you'll eventually die? One of the facts that stuck out to me as a child in social studies class was learning that in certain parts of the world at certain times in history, salt was worth its weight in gold. Has that ever been true of sociopaths in history?