The doctrine for naval aviation didn't come from the aircraft designers... it came from the naval aviation component of the navy. Machine guns were used effectively, the issue was understanding the combined effect that artillery and machine guns together would have on the modern battlefield, combined with the challenge of turning masses of new conscripts into soldiers. Those issues were resolved with time in various ways... by soldiers. Armor was not ignored, in fact many of its issues resulted from it being fielded before the kinks had been worked out, however it was integrated into a combined arms team by, you guessed it, soldiers.
Planes
Anthony Fokker, for all his poor business practises and personal unpleasantness, recognised prior to 1918 that aircraft could make attacks against ships and so battleships would need to be escorted.
HMS Prince of Wales was sunk by aircraft in 1941, shocking the naval establishment who hadn't realised that a surface ship sailing under hostile skies without an escort is in danger.
That's a 23 year gap between the designers (Fokker wasn't even an engineer) recognising the future doctrines and the admirals catching up with them.
Machine Guns
One of the forerunners of the machine gun was the Belgian Mitralleuse, which was updated and adopted in France under the weapons developer de Reffye, and was able to achieve the then-unheard-of rate of fire of 100 rounds per minute. During the Franco-Prussian war this weapon was enormously misused by the military establishment which viewed it as an artillery piece rather than as infantry support. De Reffye had this to say on the matter:
"The use of the Mitrailleuse no longer has anything in common with that of normal cannon, the employment and task of this piece deeply modify artillery tactics… Very few officers understand the use of this weapon which, however, is only dangerous by the manner one uses it… The partisans of the mitrailleuse are found among the young who crewed them during the war; but there are far fewer among superior officers."
In this case, too, we see a weapons developer recognise the potential of a weapon and talk about the correct doctrinal use, and be ignored by generals who are still used to conventional thinking.
Tanks
In 1912, Lancelot de Mole of Australia wrote to the British government with detailed schematics for a self-propelled armoured vehicle which would allow mobile warfare to be conducted with complete immunity to small arms fire, boggy ground and barbed wire. It was ignored. In 199 the following was written about him by a War Office bureaucrat:
"We consider that he is entitled to the greatest credit for having made and
reduced to practical shape as far back as the year 1912 a very brilliant invention which anticipated and in some respects surpassed that actually put into use in the year 1916. It was this claimant's misfortune and not his fault that his invention was in advance of his time, and failed to be appreciated and was put aside because the occasion for its use had not then arisen."
Meanwhile, the attitude of the military leaders can be summed up with this wonderful quote from Winston Churchill which was published in 1930:
"It is a shame that [modern] war should have flung all this [spectacle] aside in its greedy, base and opportunist march, and turn instead to chemists in spectacles, and chaffeurs pulling the levers of aeroplanes and machines. But in Aldershot in 1895 none of these horrors had broken upon mankind. The Dragoon, the Lancer, and above all, we believed, the Hussar still claimed their time-honoured place on the battlefield. War, which used to be cruel and magnificent, has now become cruel and squalid. In fact, it has been completely spoilt. It is all the fault of Democracy and Science... instead of a small number of well-trained professionals championing their country's cause with ancient weapons and the beautiful intricacy of archaic maneuver... we now have entire populations... pitted against one another in brutish mutual extermination, and only a set of bleary-eyed clerks left to add up the butcher's bill. From the moment Democracy was admitted to, or rather forced itself upon, the battlefield, war ceased to be a gentleman's game."
To this statement I have nothing else to add. (The second half of it isn't really germane to this discussion but it's so revealing a quote that I didn't want to cut it.)
Nuclear Weapons
The idea that nuclear weapons might be more useful as a threat than in actual deployment was something that, according to Oppenheimer's diaries, was well-understood by him and by several others working on the Manhattan Project in the early 1940s.
In 1950, General Macarthur urged the use of nuclear weapons in the Korean war. As a soldier he was not able to conceive of the concept of mutually assured destruction and of the idea of not using a weapon. Fortunately President Truman, who had not been in the military in World War 2 at all, overruled him.
Once again we see that the technical people (this time scientists) had foreseen how weapons would shape doctrine, while the military minds had not.
Conclusion
Engineers, weapon designers, developers, scientists - these are not soldiers. Yet for the tank, the machine gun, the airplane and the nuclear bomb they understood the ways that their weapons would be used. Military leaders, meanwhile, clung to the established concepts and only changed their doctrines grudgingly and usually only after catastrophes.
If we make war in space - which we will, I hope, not ever do - then hopefully we can be sensible enough to listen to the technical people first and let them develop the doctrines rather than making the same mistake as before.
