Trust is a function of the expected incentives of the trusted.
One way to manage their incentives is by exercising control, but there are other more friendly ways, too. For example, shared goals, community, reputation, financial rewards, reciprocity and ethics standards all provide weaker or stronger reasons to trust others.
trust is a function of control. With free software it is distributed trust and control. With proprietary Sw it is centralized trust and control.
Real life proved that centralized control is a bad idea, that is why we invented democracy and free software.