I think you might be looking at it from the wrong angle. Some of the most morally bankrupt people I've ever met are crazy intelligent. You seem to equate being a sociopath with being a moron and that is more often than not a poor assumption.

The other aspect that I think you're overlooking is that people who are wired like this are often incredibly driven people. Sure, someone on /r/entrepreneur might be willing to give up everything to pursue their dream but a sociopath is willing to lie, cheat, and steal to get what they want.