What factors can influence a company's primary goal of maximizing shareholder wealth?

There are many. Laws are one major factor - a company could often provide more wealth to the shareholders if it skirted a few laws here and there. A company may have adopted some charitable cause in the name of social responsibility that reduces shareholder wealth. A company might decide not to produce a certain type of profitable product because they have some objection to it (could be dangerous to children, is not environmentally friendly, etc.) A company might decide to remain "Made in the USA" for patriotic reasons instead of reducing cost by producing overseas.