Co-founder has nothing to do with CEO. Clearly Wozniak was the technical co-founder, not the business co-founder. I have never seen any hint of him being anything but terrible at business.
In a small company, every person has enough influence to rival the CEO and every role overlaps enough that the distinction given by titles is meaningless inside the company. Mainly the distinction given by titles determines how people market themselves outside the company where the dividing roles will appear clear for marketing purposes, which they are not in reality.