How would the DA even be able to press charges if the police do not investigate at all because they claim that the DA will not press charges? The DA does not go

How would the DA even be able to press charges if the police do not investigate at all because they claim that the DA will not press charges? The DA does not go round investigating criminal cases, they rely on the police for that. It was clearly the police who dropped the case, not the DA. Maybe the police have given up because they are correct in that the DA will not do anything, but they could just as well be blaming the DA for their own prioritization issues.