A lot of people seem to forget that MSP's effective O&D base is much larger than the Twin Cities due to the captive upper Great Lakes market. Discontinuing this captivity would basically serving a whole population on a platter to other airlines, which I doubt would even be able to profitably serve the much smaller local markets. Even if it means that the MSP hub won't be a superhub like ATL, it still ensures MSP's place as a decent sized hub, maintaning connections to most of the country and a few international destinations, like it currently does. MSP isn't going anywhere.