Re: Authority to hire services
The powers granted to the counties were (and remain) whatever the state says, and the states can change that at any time
Actually, you will find that once authority is delegated it is not so easily withdrawn, and states CANNOT just change it at any time. The same principle exists between the states and the Federal government.
In the United States the power trickles from the bottom up, not from the top down, and the power of county officials over certain things, such as county buildings and infrastructure, is almost absolute. The State's control in those areas is pretty limited, and then usually by controlling how much in the way of tax dollars flows back into the county. It would usually require a subpoena for the state to reassert control.