Paying an officer to do something low-risk like camping out next to a road for a shift isn't really expensive. Same with monitoring systems like cameras on traffic lights. Set-up cost is significant, but they probably pay for themselves within a year.
Second I know that the officer is not the only cost involved. What about maintaining a fleet of top of the line vehicles? How about paying all the support personnel such as IT Staff, dispatch, managers, etc? All of the other expensive toys carried around by the chaser?
Arguable. It depends on how badly you want [insert autonomous car producer here] to run your local police department from the cloud.
Having the rules data provided by the government is a fairly straightforward way for the vehicles to work even after the builder repudiates maintenance (maybe that is better said as 'to continue to work longer after', but whatever).
(I'm not worried about the cloud, hand-wringing and paranoia are going to make these things at least function independently or keep them off the road altogether)