Pride goeth before the fall
War starts with a bluster. Whether it is with sacrifices in the temples, parades or press conferences, young men are sent to battle with pomp and ceremony. Then, they storm the forts or the beaches or the hilltops. They die, usually horribly, foolishly, from mistakes historians will later describe as avoidable. Lessons are learned - often, they resemble lessoned already learned in previous conflicts. Force generation and employment adapts. War ends. Another one begins, the cycle repeats itself. Academics write about military incompetence; others wax poetically about zoology.
One could argue that this pattern was to be expected in the past. For the majority of human history, fighting was barely a profession and militaries were lean establishment. Modern staffs, the "brain of the army" were a very late invention. Beforehand, learning was personal, military scholarship (often surviving centuries, receiving a stature akin to holy scripture) was anecdotal and amateurish.
We have surely advanced since. Everywhere military "back office" has ballooned, the fighting force has been professionalized. Military academies were established and some places, education programs were even enshrined by law. The military profession has moved from mainly art to science and art.
Militaries started trying to design themselves for the next war, establishing bureaucracies and process that move vast resources for that purpose. Yet militaries seem to keep getting it wrong. For a recent example, one should look east, the Russia-Ukraine war. Prior to that conflict, the Russian military, on its face, did everything right - it had a robust and professional back office, with many educational facilities, granting advanced degrees in military art and science to officers serving many years in their positions. It undergone and extensive reform converting it from a heavy conscripted force to a lean semi-volunteer army. It modernized, introducing new kit in every service and branch. It had many experienced officers from recent conflicts from Chechnya to Georgia and Syria to Ukraine itself. It was, on the paper at least, a serious threat, a force to be reckoned with.
Yet, it too collapsed on the shores of reality and had to adapt and relearn lessons that were supposed to have already been known. This story is not unique. It repeats in many forms and languages. To the military professional observing from the ringside, this should raise serious questions about how militaries generate forces. Could it be that we are indeed incompetent? Are the tales of lions and donkeys true?
It is, of course, complicated

It is, indeed, complicated. Modern militaries like to engineer their forces. Force generation entails lengthy planning processes, involving many stakeholders and moving parts, over multiple years, meant to create the right force to win the first battle. To facilitate this design process, the military tries to holistically look at the various elements creating military power. These elements, referred to by the acronym DOTMLPF, describe everything that should go into the giant cocktail that is a military force - Doctrine, Organization, Training, Material, Leadership (and education), Personnel and Facilities. In recent years, a new ingredient was added to the recipe - Policy. With these powers combined, the right and lethel force is supposed to be created. This alphabet soup, however, only describes part of the very complicated picture and neglects the relationship between the various elements comprising military power. Depiction closer to reality would look something like this:
A military force is an organ (ideally) larger than the sum of its parts. These parts include "hard" elements (everything we can describe and measure), "soft" elements (other things we can't comfortably describe, but rather talk with more hand waving about), non-military elements and unknown variables. Analysts and pundits tend to focus on the "shiny objects" that a...