You're on to something here, no doubt. Pervasive anger and fear will always create the conditions for a paradigm change.
The focus on this thread is on the Republican party being in "disarray". But perhaps what we are witnessing is the utter disintegration of the Democratic Party. Maybe that's all that's happening.
I'm not sure it matters that the Trump coalition differs in composition from what was the Reagan coalition, because it's going to have the same effect.
I think the story of the election will be how the traditional Dem party voting blocs simply stayed home.
One can only hope.