I’m not sure what you mean by this, and I don’t think you do, either. County sheriff departments and their associated and subsidiary agencies often comprise many functions including operating jails and juvenile detention facilities, providing animal control services, staffing and performing search and rescue operations, inland waterway patrol, the county coroner’s office, court baliffs, parole officers, process servers, et cetera in addition to law enforcement which are important to people in unincorporated communities and rural areas not served by municipal agencies, and in many cities they supplement municipal services in many areas. Sheriff’s departments are not a part of the judiciary, and, except for the office of sheriff and sometimes coroners, are not elected officials. I don’t know what you think would take over these roles, or if they could just be dispensed with, but while there is plenty of discussion to be had about overpolicing, corruption and lack of standards in (typically underfunded) sheriff departments, et cetera, these agencies provide crucial services that are not “largely archaic” or ancillary.
While coastal New Jersey and the Deleware River region down to the Philadelphia metro region are pretty heavily developed, there is plenty of rural and unincorporated areas in New Jersey not served by any municipal law enforcement and pretty sparsely covered by the NJSP. Get off I-95 and go east anywhere south of Trenton and you’ll find it nicely bucolic quickly, and of course the massive Jersey Pine Barrens are almost wholly unserved by any law enforcement or other services.
This varies from state to state, but while the most public view of state-level law enforcement is highway patrol/state troopers who mostly patrol major highways, these agencies also have an investigative function which provides continuity of investigative authority for intrastate crimes that cross individual jurisdictions, and are often the key organization investigating things like financial crimes, serial rape/murder, child sexual abuse, et cetera that span multiple counties, as well as providing an oversight function for crimes committed by local and county law enforcement within the state, and provide security and protective services for senior state government officials and major facilities. But they are not generally first responders to any kind of non-vehicular local crime and are not typically constituted to respond in force to particular incidents.
Stranger