That all depends on how we define success. Companies run through phases: sometimes they're profitable and sometimes they're not. Do we rate leaders on profit margin alone? It's not always possible.
You can have an exceptional leader who is well-liked and not perform well. Maybe the leader wound up in the wrong position or with the wrong company. What we forget is that leaders don't run alone. They are bound to their own bosses and the interests of all stakeholders. Other times, it can be a personality flaw, such as a weakness in assertiveness or influence.
What most good people offer the complexities of leadership is interpersonal expertise. They're able to relate to others in ways many find unthinkable. They give the professional environment a homely feeling, encourage comradeship at best and some attempts at cooperation at least. Maybe they don't always accomplish what they set out to do - implement a new strategy, pass a new policy, introduce a new product - but the process was not as demeaning or energy sapping as one led by aggressive leaders. That's important, because aggressive people fail too, but they isolate others along the way. Not the good person. This individual knows that regardless of the outcome, what matters is the delivery and how you made individuals feel in your quest for whatever the definition of success is. And that is precisely why good people make exceptional leaders.