There are two ways to kill guerrilla warfare: sensor density and armor advancements. Battletech mostly has armor advancements in its court (but does have some particularly insane sensor tech as well, likely due to the fact that the armor is designed against DEWs in general) but in RL and my future-history setting's case, its sensor density. As sensor density increases, the ability to do guerrilla warfare decreases (alongside what I would call the 'minimum firepower requirement' for combat operations, but that is useless without the ability to get that firepower where it needs to be, usually via knowing where that firepower is most useful).
Essentially, when any major force can literally know when you take a shit as you're doing it, guerrilla warfare kind of vanishes... and if armor makes that incredibly hard as well (via pushing the 'minimum firepower requirement' to such levels that some dudes with MGs and rockets won't cut it), then it is a certainty.