Not just lack of out of the box thinking, also the inherent outdatedness of the corpus of documented war in general. There's even a saying describing the proble

Not just lack of out of the box thinking, also the inherent outdatedness of the corpus of documented war in general. There's even a saying describing the problem, "fighting the last war". Which basically means that human strategists are already more like GPT than they should. The problem is further compounded (beyond inherent outdatedness) by the general scarcity of the corpus, fortunately there just hasn't been that much war written by recent history.