"The more things change the more they stay the same" This has been an ongoing issue for what seems like forever.
IMO as long as most government entities, be it local state or federal, are more concerned about their "power" nothing significant will come of this issue. especially the sharing of resources between organizations.
Another issue that IMO has limited the expansion of this concept is the perceived security issues, what security manager would want to let uncontrolled masses into the same space that government officials were trying to do their work.
This concept seems to have had various degrees of success in "smaller" commuter communities, two communities that come to mind are Madison Al and Tomball Tx, where the tax base is insufficient to support separate facilities for most functions and because a significant percentage of the people have at least some involvement within the community.