It didn’t seem like Rummy knew much about war either. I said back in 2003 that a force of 150,000 soldiers could not fully secure a metropolis the size of Baghdad without the cooperation of the citizens, As far as I know it was the only accurate prediction of the the Iraq War.
I'll just add that studying history gives people better perspective. It enables one to imagine the range of possibiities from a course of action so that little things are not blown out of proportion. That is sorely lacking in all coverage of the Iraq war.