This is exactly what the radicals want (though I don't think they are pursuing it deliberately): They want an increasingly radical Republican party because it gives them power to enact what they want when Democrats are in power, because those who would otherwise object have nowhere else to go. Similarly, the Republican radicals love the radicalization of the Democrats for the same reasons.

Two magnets with the same poles forcing each other further apart, leaving those of us in the middle to pound sand. At some point I wonder if there will be a "fuck you" movement in the center. Probably not; we'll just stop voting, or vote largely on prior momentum, and despair.