George Zimmerman was part of neighborhood watch, what do you think will replace police?
A variety of domain-specialized community services organizations, many of which will have enforcement components, some armed, and probably at least one of which is investigatory/enforcement focussed, but no single monolithic paramilitary organization.
Not a neighborhood watch, but more like how federal law enforcement, and despite the fact that “state police” organizations do exist, that of most states, is organized.
Honestly? My fear is that governments will privatize policing. Because that's the policy that both parties can agree on / take bribes from.