Last author here. Good point, I agree that the move to an entirely self-sustaining machine economy would require extra time, and that would drag out the time to extinction even the worst case scenario by this mechanism. And, if caught early enough it's possible that a revolution could reverse the trend, at least temporarily and locally.
However, we tried to address the point about why a revolution would be difficult: We're assuming we're in a world where there are better machine alternatives for almost everything. So the police and military would already have been hollowed out. And the power of a general strike would be greatly diminished. It'd also be much less costly for the state to harshly punish early signs of dissent.
However, we tried to address the point about why a revolution would be difficult: We're assuming we're in a world where there are better machine alternatives for almost everything. So the police and military would already have been hollowed out. And the power of a general strike would be greatly diminished. It'd also be much less costly for the state to harshly punish early signs of dissent.