This is called the Agency Problem and is a fundamental challenge of organizing humans. If you start separating who makes decisions (e.g. the board) from who benefits (theoretically, shareholders), then over time the former will subvert the latter. But there is no simple fix if you want investment returns without managing the company.

This is one of the better reasons to bet on startups in a world where power accumulates advantage. During the growth stage of a startup, the incentives of owners, managers and team members are much more aligned than they will be later in the trajectory.