American companies view extroverted personality traits as "management material." They're sociable, talkative, outgoing, confident, positive, friendly, and open. Managers are extroverted. Extroversion tends to increase as you look at managers higher in an organization. Your C-level executives all tend to be the most extroverted people in the company.
Education matters when looking for a managerial position. But, hiring managers downplay education all the time. What matters most of all are things like "company fit," aka personality. Do you act like a manager? In the US, that often means: are you extroverted?
Companies would rather promote an extroverted employee with some job experience over any introverted MBA regardless of the MBA's job experience. That extroverted employee just has "management material" written all over him.