It took a study? All you have to do is work corporate and you'd know it. I've an adopted nephew with a crap load of disorders but also high intelligence. My brother and s-I-l work very hard on trying to make him as functional as possible with whatever tools of living he can handle. I said to my brother a few years back when the shrinks were telling my family to just give up on the kid, "for all we know now, that kid could wind up being a corporate president one day." And I wasn't kidding.
Within the multi-national I was with were many very smart and very nice people, mostly. But also we had some who should not have been there. Not only can sociopaths rise to the top by their own manipulations, but I even saw one guy, who was about the most horrible person I ever met, rise to towards the top by previous managers moving him up in other divisions just to get rid of him.
I've seen that at a couple of levels. My own manager did that to my receptionist who was a pathologic liar. Because it isn't so easy to fire people so he recommended her for a better position out of our department as soon as that opportunity became available.
It's not really excusable but understandable. Sometimes these guys are between a rock and a hard place. She was awful to work with. I actually did most of my work from home and then I'd come in after hours for whatever I needed to do in the office. So to get her out of our way was a blessing, though that then became someone else's nightmare. And that's often how those people rise.