Dude, unfettered Libertarianism would be a nightmare. You would have self-appointed arbiters of truth and justice who would have the morals of an ape meting out comeuppance.
As soon as Libertarianism hit, shit would go sideways and police would be conscripted all over again.
The dirty corrupt cops at the top love it when people throw out the baby with the bathwater. Because they can say, "See? They just hate cops."
There will always, always, ALWAYS be cops.