I think it’s almost tautological - The ability and will to accumulate wealth, by any means. That’s not necessarily greed, but after a point it basically always is.

Some skilled people, some union workers, some talented creatives, earn decent money because they, by differing means, have the ability to leverage their skills for above-average money. Obviously, in a free market, that leverage has a limit.

If you can get wealth by murder, by abuse, if you can offset your expenses by dooming the human race to the extinction, if you can bring in more sales by destruction, genocide and theft, if you can avoid helping others, caring about people, righting your wrongs or repairing damages, then you will do extremely well. Because those things minimise your outgoings and maximise your incoming.

“Successful” people typically do these things because of pathological greed, but some might do those things because they’ve build a fake world in their head and don’t accept reality, or simple sociopathy. Often a combination of all three. The common thread is an ability and will to accumulate capital by any means.

See: All billionaires.