Actually, there is only a "safe world" in academia for very few. Besides, as you've noted, the rewards are entirely different, and so are the motivations. A CEO is going to focus on making money (for himself and for the company, usually in that order), while academics rarely make all that much money. In exchange, they have more stable jobs, and used to have good benefits and retirement plans. But no professor worth his or her salt is going to sit around and do nothing. That would be humiliating, to add nothing to the body of knowledge, and to largely be irrelevant. Not all people respond to the same types of motivators.
I've spent a considerable amount of time in both worlds. The big difference in the academic world is how people think, something you get hit with in that first PhD class. You are trained to question things, not to jump to conclusions, and to eschew dogma. I'm not sure that kind of thought process is entirely ideal for a CEO, although one would hope he or she would have some of that objectivity. CEOs need to make decisions with relative speed, something that may require subjectively avoiding facts or filling in blanks. My experience in the academic world is that things move slower, because you have to get the necessary data together.
There are shitty CEOs out there, most of whom ended up in their positions because of who they were (birth). But to get to the top in either field requires an amazing skill set, albeit a different one.