Neoliberalism is super entrenched here. It is almost impossible to create a state/county/municipal IT department that would actually have enough sysadmins. All such departments rely almost entirely on external suppliers. One way this happens are salary controls. It is impossible to hire someone and give him the market rate, but it is trivial to tender the work associated with such position to a random external company for thrice the market wage.
This effectively means that the critical advantage of FLOSS - just install it and see if it works for the users - is effectively killed by the red tape. Only software that someone actively sells can ever make it through.
EDIT:
And to be clear, this is not about customer support and whatnot. Number one complaint from most of the public servants who contract out IT services have been that the suppliers are not helping them, are overcharging them and in some instances they even threaten and withhold documentation and read access to their software databases.