The Walmart analogy might be close to the truth. My knowledge of ACO's is limited, so the following could be off base.
ACO's can save some government money, but will also probably screw the small providers (doctors, nursing homes, and such). The main provider (hospital system?) gets a lump some and contracts with the smaller providers at a price likely lower than what those providers currently get. Of course, those small providers will be fighting to get whatever scraps they can get from the ACO in order to stay in business.
The ACO gets stronger, the other providers get weaker, and the government will ultimately need the ACO, due to the lack of competition, as much as the ACO needs the government.
ACO's can save some government money, but will also probably screw the small providers (doctors, nursing homes, and such). The main provider (hospital system?) gets a lump some and contracts with the smaller providers at a price likely lower than what those providers currently get. Of course, those small providers will be fighting to get whatever scraps they can get from the ACO in order to stay in business.
The ACO gets stronger, the other providers get weaker, and the government will ultimately need the ACO, due to the lack of competition, as much as the ACO needs the government.