Was the paper arguing that this is true for the first round of combat, and where smart attackers know when to call it off? I didn’t quite follow the paper since the whole Mr T thing was distracting.
Intuitively I’d guess that the size of bad luck depends mostly on force composition. If the attacker uses planes, sure they can lose big. If the defender has planes, they can lose big too. Defenders can also lose really big if you take their capital (or to a lesser extent if you take WEU or SEU).
For single round combats, most of the time attackers can retreat if they see their luck going bad after the first round - and that makes a huge difference.