Just because A implies B (successful businessman implies good at sports when kid) doesn't mean B implies A (good at sports implies good businessman).
Most new businesses go bust. It seems the skills that give a business the best chance are also those that tend to lead success on the sports field. But it's quite likely that successful businesses are lead/run by people who have the ability to do well (but not excel) at sport. If they excel they stay in sports. If they don't, when they go into business they are more likely to excel there than the general populace as a whole.