I hope they do. But the fatal flaw of patient attribution needs to be fixed. None of this can work without patient compliance, and other than the hope that such well-coordinated care organizations will sell themselves to patients and make them want to receive all their care under one roof, there's nothing to compel them to do so.
We'll really find out if this project is viable only when it comes time for ACOs to sign up for their second contracts, which will require two-sided risk. An educated guess based on the initial response is that, without some way to ensure that ACOs have some control over where patients receive care, the risk rules of that second contract might make initial participants think twice.
Until then, success will be gauged only on the hype.