What I see happening isn't an orgiastic display of violence or beautiful if dangerous fast collapse. I see a slow dissolution as capitalism winds down and becomes ever more sclerotic, it withdraws from its frontiers and hinterlands and suburbs and ends up being in a few great (probably only metaphorical but perhaps literal) walls where they jealously guard their global cities.

I don't think anywhere will balkanize, maybe a few more breakaways are left where tensions are highest or have been - like Quebec possibly or the Republicans winning in Northern Ireland or Scotland etc. Instead of balkanization, one day you'll wake up after going to work and realize the national government just isn't part of your life anymore. Yeah sure, it claims to be in control and you can vote for it - but it doesn't actually have any power to do anything, it was all devolved and dissolved itself as capitalisms economic base for Nation-States ate itself.

Like I bet there will still be a President that lives in Washington DC and a bit of the Boston to Washington city is all it actually has control over - but still claims the whole contiguous continental US.