Because the set of criminals used in the research are confirmed psychopaths, so it's the only way to conduct such a study. You cannot round up Hedge Fund managers for such a study. But this also makes what you're saying somewhat non-falsifiable. Highly successful people basically are extremely driven and ambitious, and they work all the time. (I'm assuming you relate to this.) But there is no evidence (as far as I know) correlating tendencies to be extremely ambitious, and psychopathic tendencies such as inability to feel empathy. Although, obviously, tendencies associated with both things may overlap, since a very ambitious person is more likely to appear very selfish to an outside observer.

Also, many actual confirmed geniuses like Einstein, Alan Turing, etc. clearly were simply obsessed (which is really just a more negative way of saying "very enthusiastic") about their work - they didn't necessarily care to become powerful men (Einstein famously turned down the Presidency of Israel because it was boring to him). These people were just really, really interested in the problems they were working on. This seems to intersect better with something like OCD rather than psychopathy - and indeed, there are of course many anecdotes around Princeton University of Einstein exhibiting OCD tendencies.