Things are more and more complicated (interacting, and also wide, dense, fast-moving...), and therefore unpredictability grows. This is true for nearly everyth

Things are more and more complicated (interacting, and also wide, dense, fast-moving...), and therefore unpredictability grows. This is true for nearly everythoing, and war reflects it, as up to the Industrial Revolution things (strategy, tactics, weaponry...) evolved gradually. Nowadays nobody knows anymore how all this really works, therefore there is less and less way to predict (how/what/why/when/...) sufficiently accurately in order to prepare/act adequately (for example to equip soldiers). Hence the need for "something which can cope with any situation". Fun fact: this 'something' has to be complicated, adding up complication to the complicated global state of affairs, nurturing the very cause of the underlying challenge.