so out of a ninja alliance of more then 70 thousand, the fact that most of the alliance has been killed isnt enough casualties?
The war has been very brutal. The problem is though, that kishi didnt spend time showing all the non main characters fighting(which if he did people would complain anyways).
Kishi has already killed off 3+ main characters already (shikaku, inochi, neji, and apparently soon shikamaru)
The war still isnt over and kishi can still have more of main characters dieing. It would be dumb, to just kill all the main characters though.