The expected deaths are N+P_nM in the human-combatant case and P_yM in the autonomous combatant case, with a difference in fatalities of (P_y−P_n)(M−N). Given how much larger M (~1-7 Bn) is than N (tens of thousands at most) it only takes a small difference (Py−Pn) for this to be a very poor exchange.
Thanks for writing this!
I believe there’s a small typo here:
Shouldn’t the difference be (P_y−P_n)M−N ?