I don't expect any section of the country at this point in time to become a political monolith. We have that situation in many of our cities, and it is highly dysfunctional. While certain interest voters will keep voting for the same party blindly no matter how bad things get under that party, the broader bloc of voters will not. And because things always get bad under extended periods of one party rule, regardless of which party it is, this will result in some shift in political alliances that lead to a rebirth of the two party system.
Politicans are like parasites. Much as I don't like the Democrats, I have never wished for one-party Republican rule, because each party only serves its constituent voters well when faced with competition, and when threatened with losing their power. If they are not threatened with losing their power, they will suck the taxpayers dry. The relatively recent existence of a two-party system in New York City, at least at the mayoral level, has a lot to do with why the city is doing so much better than it was when the mayors were automatically Democatic. The power of that parasitic political machine has been checked somewhat by the election of people from outside of it.
These things can't be predicted, but Democratic dominance in certain New England states, particularly Connecticut, is dependent upon a de facto alliance between rich suburbanites and poor inner city minorities. This is not a match made in heaven, and it cannot be assumed that it can continue indefinitely.
When I lived in MA in the 80's one of the fall-back positions for the GOP was the deep tradition of local control in much of New England. When too many state resources get diverted to the big cities there is usually a local backlash from outlying areas. If that tradition still exists it may provide a basis for a party centered on the local issues and away from the national issues.