Special attention. Financial support. Housing security. Food. Child care. Transportation. Authority, guidance or direction. Social connections. Employment.
These are all forms of support that abusers will offer as a way of controlling people. The more usefulness or value an abuser has, the less likely people will call out their abuse and hold them accountable. This is why victims stay with their abusers, and why people allow abusers to continue operating within their community – because they are providing enough usefulness, value or reinforcement, that to hold them accountable or kick them out would also mean losing the value that they bring. The only way to oust an abuser is to offer more (and easier) value than they do.
If you are not offering what the abuser is offering – or better – then you will never have the power to oust the abuser. Do not blame or question victims for staying unless you are willing to support them in the ways that the abuser does, because you will lose.