You have underestimated the savings by at least two orders of magnitude. Imagine no locks, no alarms, no armies, no guns. If you add up all the work done securing “stuff”, it’s more than the work it took to make the “stuff” in the first place.
There are models, but making them work at scale is the challenge. I have spent time in rural Haiti where there is no organized police presence. Antisocial behavior is risky because everyone depends on everyone else in a resource limited environment. Extreme antisocial behavior is dealt with by mob violence. In comparison, I think the no police model did less harm overall than the criminal justice system model.
However, where there are more resources, there is more potential for systems of organized exploitation and domination. The concept of a democratically controlled police force is one model of a solution to this problem. However, the cost of a criminal justice system will continue to grow and become unsustainable as long as social justice in not addressed.